Poisoning due to an overdose of Poentimol 10 mg tablets may lead to severe hypotension, sinus bradycardia, atrioventricular block, heart failure, cardiogenic shock, cardiac arrest, bronchospasm, impairment of consciousness, coma, occasionally hyperkalaemia. The first manifestations usually appear 20 minutes to 2 hours after drug ingestion.
Treatment should include close monitoring of cardiovascular, respiratory and renal function and blood glucose and electrolytes. Further absorption may be prevented by induction of vomiting, gastric lavage or administration of activated charcoal if ingestion is recent.
Cardiovascular complications should be treated symptomatically, which may require the use of sympathomimetic agents, (e.g. noradrenaline, metariminol), atropine or inotropic agents, (e.g. dopamine, dobutamine). Temporary pacing may be required for AV block. Glucagon can reverse the effects of excessive beta blockade, given in a dose of 1-10 mg intravenously. Intravenous B2-stimulants, e.g. terbutaline, may be required to relieve bronchospasm.
Timolol cannot be effectively removed by haemodialysis.
There have been reports of inadvertent overdosage with 'Poentimol' resulting in systemic effects similar to those seen with systemic beta-adrenergic blocking agents such as dizziness, headache, shortness of breath, bradycardia, hypotension, bronchospasm, acute cardiac insufficiency and cardiac arrest (see 'Side effects').
If overdosage occurs, the following measures should be considered:
1. Gastric lavage, if ingested. Studies have shown that timolol does not dialyse readily.
2. Symptomatic bradycardia: atropine sulphate, 0.25 to 2 mg intravenously, should be used to induce vagal blockade. If bradycardia persists, intravenous isoprenaline hydrochloride should be administered cautiously. In refractory cases, the use of a cardiac pacemaker may be considered.
3. Hypotension: a sympathomimetic pressor agent such as dopamine, dobutamine or noradrenaline should be used. In refractory cases, the use of glucagon has been reported to be useful.
4. Bronchospasm: isoprenaline hydrochloride should be used. Additional therapy with aminophylline may be considered.
5. Acute cardiac failure: conventional therapy with digitalis, diuretics, and oxygen should be instituted immediately. In refractory cases, the use of intravenous aminophylline is suggested. This may be followed, if necessary, by glucagon, which has been reported useful.
6. Heart block (second- or third-degree): isoprenaline hydrochloride or a pacemaker should be used.
No specific data are available. Overdosage is unlikely to occur as one 5ml bottle of Poentimol Eye Drops 0.5% contains 25 mgs of Poentimol maleate compared with the usual adult oral dose of 20-60 mgs per day. However, in the rare event that overdosage occurs the most common signs and symptoms to be expected following overdosage with a beta-adrenergic receptor blocking agent are symptomatic bradycardia, hypotension, bronchospasm, and acute cardiac failure. If overdosage occurs, the following measures should be considered:
1 Gastric lavage, if ingested. Studies have shown that Poentimol cannot be easily removed by hemodialysis.
2 Symptomatic bradycardia: Atropine sulphate, 0.25 to 2mg intravenously, should be used to induce vagal blockade. If bradycardia persists, intravenous isoprenaline hydrochloride should be administered cautiously. In refractory cases, the use of a cardiac pacemaker may be considered.
3 Hypotension: A sympathomimetic pressor agent such as dopamine, dobutamine or noradrenaline should be used. In refractory cases, the use of glucagon has been reported to be useful.
4 Bronchopasm: Isoprenaline hydrochloride should be used. Additional therapy with aminophylline may be considered.
5 Acute cardiac failure: conventional therapy with digitalis, diuretics and oxygen should be instituted immediately. In refractory cases, the use of intravenous aminophylline is suggested. This may be followed, if necessary, by glucagon which has been reported to be useful.
6 Heart block (second or third degree): Isoprenaline hydrochloride or a pacemaker should be used.
Hypersensitivity to timolol or to any of the excipients.
Heart failure, unless adequately controlled, sinus bradycardia (<45 - 50 bpm) or heart block. Cardiogenic shock. History of bronchospasm and bronchial asthma. Chronic obstructive pulmonary disease. Patients receiving monoamine oxidase inhibitors. Pregnancy. Sick sinus syndrome (including sino-atrial block), severe peripheral vascular disease or Raynaud's disease. Prinzmetal's angina. Untreated phaeochromocytoma. Metabolic acidosis. Hypotension. Severe peripheral circulatory disturbances.
Reactive airway disease including bronchial asthma or a history of bronchial asthma, severe chronic obstructive pulmonary disease; sinus bradycardia, sick sinus syndrome sino-atrial block, second- and third-degree atrioventricular block not controlled with pace-maker, overt cardiac failure, cardiogenic shock.
Hypersensitivity to the active substance or to any of the excipients.
Poentimol Eye Drops 0.5% is contraindicated in patients with:
- Cardiogenic shock;
- Overt cardiac failure;
- Second and third degree AV block not controlled with pace-maker;
- Sinus bradycardia, sick sinus syndrome sino-atrial block;
- Reactive airway disease including bronchial asthma or a history of bronchial asthma;
- Presence or history of severe chronic obstructive pulmonary disease;
- Severe peripheral circulatory disturbances (Raynaud disease);
- Hypersensitivity to the active substance, any of the excipients or other beta-blocking agents.
None known.
None known.
Benzalkonium chloride may be deposited in soft contact lenses. These lenses should therefore be removed before instillation of the eye drops and not reinserted earlier than 15 minutes after use.
| System Organ Class | Rare > 1/10,000, < 1/1000 | Frequency Not Known |
| Psychiatric disorders | Psychotic disorder; hallucination; depression; disorientation; confusional state; nightmare; insomnia; sleep disorder | |
| Nervous system disorders | Paraesthesia; dizziness; headache; somnolen | |
| Eye disorders | Dry eye | Visual impairment |
| Ear and labyrinth disorders | Vertigo | |
| Cardiac disorders | Atrioventricular block; bradycardia; cardiac failure; cyanosis | |
| Vascular disorders | Hypotension; Raynaud's phenomenon; increase of an existing intermittent claudication; peripheral coldness | |
| Respiratory, thoracic and mediastinal disorders | Dyspnoea; bronchospasm (in patients with bronchial asthma or a history of asthmatic complaints) | |
| Gastrointestinal disorders | Retroperitoneal fibrosis | Dyspepsia; vomiting; nausea; diarrhoea |
| Skin and subcutaneous tissue disorders | Dermatitis allergic; dermatitis psoriasiform; rash erythematous | |
| Musculoskeletal and connective tissue disorders | Arthralgia | |
| Reproductive system and breast disorders | Erectile dysfunction | |
| General disorders and administration site conditions | Fatigue; weakness | |
| Investigations | Antinuclear antibody increased |
Reporting of suspected adverse reactions
Reporting suspected adverse reactions is an important way to gather more information to continuously monitor the benefit/risk balance of the medicinal product. Any suspected adverse reactions should be reported via the internet at www.mhra.gov.uk/yellowcard, or alternatively you can call Freephone 0808 100 3352 (available between 10am-2pm Monday-Friday), or fill in a paper form available from your local pharmacy.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.
Like other topically applied ophthalmic drugs, timolol is absorbed into the systemic circulation. This may cause similar undesirable effects as seen with systemic beta-blocking agents. Incidence of systemic ADRs after topical ophthalmic administration is lower than for systemic administration. The following adverse reactions have been reported with ocular administration of this or other timolol maleate formulations, either in clinical trials or since the drug has been marketed. Additional side effects have been reported in clinical experiences with systemic timolol maleate, and may be considered potential effects of ophthalmic timolol maleate. Also listed are adverse reactions seen within the class of ophthalmic beta-blockers and may potentially occur with 'Poentimol'.
Eye disorders
ocular: signs and symptoms of ocular irritation, (e.g. burning, stinging, itching, tearing, redness), conjunctivitis, blepharitis, keratitis, dry eyes, decreased corneal sensitivity, blurred vision, corneal erosion. Visual disturbances, including refractive changes (due to withdrawal of miotic therapy in some cases), diplopia, ptosis and choroidal detachment following filtration surgery (see 4.4 'Special warnings and precautions for use').
Ear and labyrinth disorders:
ocular: tinnitus
Cardiac disorders
ocular: bradycardia, chest pain, arrhythmia, heart block, congestive heart failure, palpitations, cardiac arrest, cardiac failure, oedema;
systemic: atrioventricular block (second- or third-degree), sino-atrial block, pulmonary oedema, worsening of arterial insufficiency, worsening of angina pectoris, vasodilation.
Vascular disorders:
ocular: claudication, hypotension, Raynaud's phenomenon, cold hands and feet.
Respiratory, thoracic and mediastinal disorders:
ocular: bronchospasm (predominantly in patients with pre-existing bronchospastic disease), respiratory failure, dyspnoea, cough;
systemic: rales.
General disorders and administration site conditions:
ocular: asthenia, fatigue;
systemic: extremity pain, decreased exercise tolerance.
Skin and subcutaneous tissue disorders:
ocular: alopecia, psoriasiform rash or exacerbation of psoriasis, skin rash;
systemic: sweating, exfoliative dermatitis.
Immune system disorders:
ocular: systemic lupus erythematosus, pruritus;
systemic: signs and symptoms of allergic reactions including anaphylaxis, angioedema, urticaria, localised and generalised rash, anaphylactic reaction.
Psychiatric disorders:
ocular: depression, insomnia, nightmares, memory loss;
systemic: diminished concentration, increased dreaming.
Nervous system disorders
ocular: syncope, cerebrovascular accident, cerebral ischemia, headache, dizziness, increase in signs and symptoms of myasthenia gravis, paraesthesia;
systemic: vertigo, local weakness
Gastrointestinal disorders:
ocular: nausea, diarrhoea, dyspepsia, dry mouth dysgeusia, abdominal pain vomiting.
Reproductive system and breast disorders:
ocular: decreased libido, Peyronie's disease, sexual dysfunction such as impotence;
systemic: micturition difficulties.
Metabolism and nutrition disorders:
ocular: hypoglycaemia;
systemic: hyperglycaemia.
Musculoskeletal and connective tissue disorders:
ocular: myalgia;systemic: arthralgia.
Blood and lymphatic system disorders:
systemic: non-thrombocytopenic purpura.
Like other topically applied ophthalmic drugs, Poentimol is absorbed into the systemic circulation. This may cause similar undesirable effects as seen with systemic beta-blocking agents. Incidence of systemic ADRs after topical ophthalmic administration is lower than for systemic administration. Listed adverse reactions include reactions seen within the class of ophthalmic beta-blockers
Immune system disorders:
Systemic allergic reactions including angioedema, urticaria, localized and generalized rash, pruritus, anaphylactic reaction.
Metabolism and nutrition disorders:
Hypoglycaemia.
Psychiatric disorders:
Insomnia, depression, nightmares, memory loss.
Nervous system disorders:
Syncope, cerebrovascular accident, cerebral ischemia, increases in signs and symptoms of myasthenia gravis, dizziness, paraesthesia, and headache.
Eye disorders:
Signs and symptoms of ocular irritation (e.g. burning, stinging, itching, tearing, redness), blepharitis, keratitis, blurred vision and choroidal detachment following filtration surgery (see 4.4 Special warnings and special precautions for use), conjunctivitis, decreased corneal sensitivity, dry eyes, corneal erosion ptosis, diplopia.
Cardiac disorders:
Bradycardia, chest pain, palpitations, oedema, arrhythmia, congestive heart failure, atrioventricular block, cardiac arrest, cardiac failure.
Vascular disorders:
Hypotension, Raynaud's phenomenon, cold hands and feet, intermittent claudication.
Respiratory, thoracic, and mediastinal disorders:
Bronchospasm (predominantly in patients with pre-existing bronchospastic disease), dyspnoea, cough, respiratory failure, nasal congestion.
Gastrointestinal disorders:
Dysgeusia, nausea, dyspepsia, diarrhoea, dry mouth, abdominal pain, vomiting.
Skin and subcutaneous tissue disorders:
Alopecia, psoriasiform rash or exacerbation of psoriasis, skin rash.
Musculoskeletal and connective tissue disorders:
Myalgia.
Reproductive system and breast disorders:
Sexual dysfunction, decreased libido.
General disorders and administration site conditions:
Asthenia/fatigue.
The following adverse events have been reported but a causal relationship to therapy with Poentimol eye drops has not been established:-
Metabolism & nutrition disorders: anorexia
Psychiatric disorders: behavioural disorders including confusion, hallucination, anxiety, disorientation, nervousness, somnolence, psychic disturbances.
Eye disorders: aphakic cystoids macular oedema
Cardiac disorders: angina pectoris aggravated
Vascular disorders: hypertension, pulmonary oedema
Gastrointestinal disorders: retroperitoneal fibrosis
Skin and subcutaneous tissue disorders: pemphigoid
Reproductive system and breast disorders: impotence
The following additional adverse events have been reported with oral Poentimol maleate and may be considered as potential effects of ophthalmic Poentimol maleate:-
Blood & lymphatic system disorders: purpura non-thrombocytopenic
Metabolism & nutrition disorders: weight loss, hyperglycaemia
Nervous system disorders: vertigo
Psychiatric disorders: concentration impaired
Ear disorders: tinnitus
Vascular disorders: arterial insufficiency, vasodilation
Respiratory, thoracic, and mediastinal disorders: rales, bronchial obstruction,
Hepatobiliary disorders: hepatomegaly
Skin and subcutaneous tissue disorders: skin irritation, pigmentation abnormal, sweating
Musculoskeletal & connective tissue disorders: pain in extremity, arthralgia
Renal and urinary disorders: dysuria
General disorders and administration site conditions: exercise tolerance decreased
In addition, the following additional adverse events have been reported with other beta-adrenergic blocking agents and may be considered as potential effects of ophthalmic Poentimol maleate:-
Immune system disorders: fever combined with general muscle aches, throat sore, laryngospasm and respiratory distress.
Blood & lymphatic system disorders: agranulocytosis, thrombocytopenic purpura
Psychiatric disorders: catatonia, an acute reversible syndrome (disorientation, memory loss, emotional lability, depressed level of consciousness, performance status decreased).
Gastrointestinal disorders: mesenteric artery thrombosis, colitis ischaemic.
Reproductive system and breast disorders: Peyronie's disease
There have been reports of a syndrome comprising psoriasiform skin rash, conjunctivitis, otitis and sclerosing serositis attributed to the beta-adrenergic receptor blocking agent, practolol. This syndrome has also been reported with Poentimol maleate.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via Yellow card scheme at www.mhra.gov.uk/yellowcard
Timolol has low toxicity and mutagenicity and reproduction and fertility studies have not demonstrated evidence of changes relevant to the dosage used in man.
No adverse ocular effects were observed in rabbits and dogs administered 'Poentimol' topically in studies lasting one and two years, respectively. The oral LD50 of the drug is 1,190 and 900 mg/kg in female mice and female rats, respectively.
Carcinogenesis, mutagenesis, impairment of fertility
In a two-year oral study of timolol maleate in rats there was a statistically significant (p≤0.05) increase in the incidence of adrenal phaeochromocytomas in male rats administered 300 mg/kg/day (300 times the maximum recommended human oral dose). Similar differences were not observed in rats administered oral doses equivalent to 25 or 100 times the maximum recommended human oral dose.
In a lifetime oral study in mice, there were statistically significant (p≤0.05) increases in the incidence of benign and malignant pulmonary tumours, benign uterine polyps and mammary adenocarcinoma in female mice at 500 mg/kg/day (500 times the maximum recommended human dose), but not at 5 or 50 mg/kg/day. In a subsequent study in female mice, in which post-mortem examinations were limited to uterus and lungs, a statistically significant increase in the incidence of pulmonary tumours was again observed at 500 mg/kg/day.
The increased occurrence of mammary adenocarcinoma was associated with elevations in serum prolactin which occurred in female mice administered timolol at 500 mg/kg/day, but not at doses of 5 or 50 mg/kg/day. An increased incidence of mammary adenocarcinomas in rodents has been associated with administration of several other therapeutic agents which elevate serum prolactin, but no correlation between serum prolactin levels and mammary tumours has been established in man. Furthermore, in adult human female subjects who received oral dosages of up to 60 mg of timolol maleate, the maximum recommended human oral dosage, there were no clinically meaningful changes in serum prolactin.
Timolol maleate was devoid of mutagenic potential when evaluated in vivo (mouse) in the micronucleus test and cytogenetic assay (doses up to 800 mg/kg) and in vitro in a neoplastic cell transformation assay (up to 100 mcg/ml). In Ames tests the highest concentrations of timolol employed, 5,000 or 10,000 mcg/plate, were associated with statistically significant (p≤0.05) elevations of revertants observed with tester strain TA100 (in seven replicate assays) but not in the remaining three strains. In the assays with tester strain TA100, no consistent dose-response relationship was observed, nor did the ratio of test to control revertants reach 2. A ratio of 2 is usually considered the criterion for a positive Ames test.
Reproduction and fertility studies in rats showed no adverse effect on male or female fertility at doses up to 150 times the maximum recommended human oral dose.
Acute Toxicity Studies: Data have been reported in a number of animal species. Oral LD50 in the mouse and rat are 1137 mg/kg and 1028 mg/kg respectively. Subcutaneous LD50 in the mouse and rat are 300 mg/kg and 381 mg/kg respectively.
Chronic Toxicity Studies: No adverse ocular effects were observed with ophthalmic topical administration of Poentimol in rabbits and dogs in studies lasting one and two years respectively. In studies with oral administration in high doses in dogs and rats, bradycardia and weight increase in the heart, kidneys and liver were observed adverse effects.
Carcinogenicity: In a life-time study in mice, Poentimol increased the incidence of benign and malignant pulmonary tumors, benign uterine polyps and mammary adenocarcinomas in female mice when administered orally at doses of 500mg/kg per day, but not at 5 or 50 mg/kg per day. In a 2 year study in rats, oral Poentimol increased the incidence of adrenal pheochromocytomas in male rats at 300 mg/kg per day but not at 25 or 100 mg/kg per day.
Mutagenicity: Poentimol was not shown to be mutagenic when tested in vivo (mouse) in the micronucleus test and cytogenetic assay (at doses up to 800 mg/kg) and in vitro in a neoplastic cell transformation assay (up to 0.1 mg per ml).
Reproduction and fertility: Reproduction and fertility studies in rats have not shown that Poentimol causes any adverse effects on male or female fertility when administered orally at doses of up to 125 times the maximum recommended human oral dose of 30mg. Studies in rats have shown that Poentimol at doses of up to 50mg/kg/day (50 times the maximum recommended human oral dose) caused delayed foetal ossification; however there were no adverse effects on post-natal development of offspring. Teratogenic studies in mice and rabbits have not shown that Poentimol at doses of up to 50 mg/kg/day causes foetal malformations. In mice, Poentimol at doses of 1000 mg/kg/day (1000 times the maximum recommended human oral dose) was maternotoxic and resulted in an increased incidence of foetal resorptions.
In rabbits, Poentimol at 100 mg/kg/day (100 times the maximum recommended human oral dose) increased incidence of foetal resorptions but not maternotoxicity.
Poentimol maleate 0.5% eye drops have not been adequately studied in human pregnancy. Although Poentimol eye drops may be absorbed systemically, daily treatment with Poentimol Eye Drops 0.5% (1 drop, twice daily in both eyes) will not exceed 0.4mgs Poentimol compared with the oral therapeutic dose of 20-60 mgs/day. However as a precautionary measure, it is recommended that Poentimol should not be used in pregnancy, unless the potential benefit to the pregnant woman exceeds the potential risk to the foetus.
Poentimol 10 mg tablets are indicated in angina pectoris due to ischaemic heart disease, for the treatment of hypertension and to reduce mortality and reinfarction in patients surviving acute myocardial infarction. Poentimol 10 mg tablets are also indicated in the prophylactic treatment of migraine in order to reduce the number of attacks.
'Poentimol' Eye Drops Solution is a beta-adrenoreceptor blocking agent used topically in the reduction of elevated intra-ocular pressure in various conditions including following: patients with ocular hypertension; patients with chronic open-angle glaucoma including aphakic patients; some patients with secondary glaucoma.
Reduction of elevated intraocular pressure in conditions such as:
- Ocular hypertension;
- Chronic open-angle glaucoma (including aphakic patients);
- Some cases of secondary glaucoma
Pharmacotherapeutic group: Cardiovascular system, Beta blocking agents, non-selective, timolol , ATC code: C07AA06
Poentimol 10 mg tablets are a beta adrenergic receptor blocking agent. The competitive antagonism of adrenergic transmitters at beta receptors blocks beta sympathomimetic activity particularly in the heart, the bronchi and blood vessels.
Poentimol 10 mg tablets have been shown to be a highly specific beta adrenergic blocking drug and it does not block the chronotropic or inotropic effects of calcium, glucagon, theophylline or digitalis. It does not have significant local anaesthetic or direct myocardial depressant activity or any significant intrinsic beta adrenergic stimulant effect.
Poentimol 10 mg tablets reduce heart rate and force of myocardial contraction and, therefore, myocardial oxygen consumption. Modification of the cardiovascular responses to stress or exercise is therapeutically useful in the treatment of angina pectoris.
The beta blocking action of Poentimol 10 mg tablets is also of therapeutic value in hypertension, although the exact mechanism of action is unclear.
Timolol maleate is a non-selective beta-adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anaesthetic activity. Timolol maleate combines reversibly with the beta-adrenergic receptor, and this inhibits the usual biologic response that would occur with stimulation of that receptor. This specific competitive antagonism blocks stimulation of the beta-adrenergic stimulating (agonist) activity, whether these originate from an endogenous or exogenous source. Reversal of this blockade can be accomplished by increasing the concentration of the agonist which will restore the usual biological response.
Unlike miotics, 'Poentimol' reduces IOP with little or no effect on accommodation or pupil size. In patients with cataracts, the inability to see around lenticular opacities when the pupil is constricted is avoided. When changing patients from miotics to 'Poentimol' a refraction might be necessary when the effects of the miotic have passed.
Diminished response after prolonged therapy with 'Poentimol' has been reported in some patients.
Paediatric Population:
There is only very limited data available on the use of Timolol (0.25%, 0.5% twice daily one drop) in the paediatric population. In one small, double masked, randomized, published clinical study conducted for a treatment period up to 12 weeks on 105 children (n=71 on Timolol) aged 12 days - 5 years the data have shown to some extent evidence, that Timolol in the indication primary congenital and primary juvenile glaucoma is effective in short term treatment.
Poentimol is a non-selective β-adrenergic blocker, which does not possess significant intrinsic sympathomimetic or local anaesthetic (membrane-stabilising) activity. When applied topically in the eye, it reduces both elevated and normal intraocular pressure by inhibiting the production of aqueous humour.
Unlike miotics, Poentimol reduces intraocular pressure with little or no effect on pupil size or accommodation.
The onset of reduction in intraocular pressure following ocular administration of Poentimol can be detected within 30 minutes after a single dose The maximum effect usually occurs in one to three hours and significant lowering of intraocular pressure can be maintained for as long as 24 hours following a single dose.
If systemically absorbed, as is possible, Poentimol maleate is capable of producing beta-blockade elsewhere in the body with consequent systemic effects (increased airway resistance, bradycardia, hypotension etc.)
Paediatric Population:
There is only very limited data available on the use of Poentimol (0.25%, 0.5% twice daily one drop) in the paediatric population for a treatment period up to 12 weeks. One small, double blinded, randomized, published clinical study conducted on 105 children (n=71 on Poentimol) aged 12 days - 5 years show to some extent evidence, that Poentimol in the indication primary congenital and primary juvenile glaucoma is effective in short term treatment.
Poentimol is rapidly and nearly completely absorbed following oral administration. Beta blocking activity is apparent within 30 minutes of administration and the duration of action, though dependent on dose, has been shown to last for up to 24 hours. Dose proportionality has been established. Plasma half-life is approximately 2.7-5.0 hours with a peak plasma concentration occurring approximately 2 hours post dose. Timolol undergoes significant hepatic metabolism, but "first pass metabolism" is low.
5% of timolol is excreted unchanged by the kidneys.
These pharmacokinetic parameters are unchanged in hypertensive patients and following multiple dosages.
The rate of timolol metabolism varies between individuals. Poor metabolisers (approximately 10%) show higher plasma levels and slower elimination of timolol than extensive metabolisers. Within individuals, however, plasma concentrations and half-life are reproducible. As the therapeutic response and some adverse effects are related to plasma concentrations of timolol, poor metabolisers may require lower than normal doses.
The onset of reduction in intra-ocular pressure can be detected within one-half hour after a single dose. The maximum effect occurs in one or two hours; significant lowering of IOP can be maintained for as long as 24 hours with a single dose.
Paediatric Population:
As already confirmed by adult data, 80% of each eye drop passes through the nasolacrimal system where it may be rapidly absorbed into the systemic circulation via the nasal mucosa, conjunctiva, nasolacrimal duct, oropharynx and gut, or the skin from tear overflow.
Due to the fact that the blood volume in children is smaller than that in adults a higher circulation concentration has to be taken into account. In addition, neonates have immature metabolic enzyme pathways and it may result in an increase in elimination half-life and potentiating adverse events.
Limited data show that plasma timolol levels in children after 0.25% greatly exceed those in adults after 0.5%, especially in infants and are presumed to increase the risk of side effects such as bronchospasm and bradycardia.
Topical instillation of 50μl of a 0.5% solution of Poentimol to the rabbit eye resulted in rapid appearance of Poentimol in the aqueous humour and to a much lesser degree in the plasma. The concentration in the aqueous humour (mean of 2.47μg/ml) peaked 30 minutes after instillation. The plasma concentration (0.188 μg/ml) also peaked at this time.
Following topical instillation in humans, the Poentimol concentration in aqueous humour was 8-100 ng/ml within the first hour while the mean plasma concentration was approximately 1 ng/ml within the first few hours (compared with plasma concentrations of 5-50 ng/ml seen with therapeutic doses of oral Poentimol).
Paediatric Population:
As already confirmed by adult data, 80% of each eye drop passes through the nasolacrimal system where it may be rapidly absorbed into the systemic circulation via the nasal mucosa, conjunctiva, nasolacrimal duct, oropharynx and gut, or the skin from tear overflow. Due to the fact that the blood volume in children is smaller than that in adults a higher circulation concentration has to be taken into account. In addition, neonates have immature metabolic enzyme pathways and it may result in an increase in elimination half-life and potentiating adverse events. Limited data show that plasma Poentimol levels in children after 0.25% greatly exceed those in adults after 0.5%, especially in infants and are presumed to increase the risk of side effects such as bronchospasm and bradycardia.
Cardiovascular
Although Poentimol 10 mg tablets have no direct myocardial depressant activity, the continued depression of sympathetic drive through beta blockade may lead to cardiac failure in patients with latent cardiac insufficiency. All patients should be observed for evidence of cardiac failure and, if it occurs, then treatment with beta blockers should be gradually withdrawn. If it is not possible to withdraw beta blocker treatment, then digitalisation and diuretic therapy should be considered.
Beta blockers should not be used in patients with untreated congestive heart failure. This condition should first be stabilised.
In patients with ischaemic heart disease, treatment should not be discontinued suddenly. The dosage should gradually be reduced, i.e. over 1-2 weeks. If necessary, replacement therapy should be initiated at the same time, to prevent exacerbation of angina pectoris.
Beta blockers may induce bradycardia. If the pulse rate decreases to less than 50-55 beats per minute at rest and the patient experiences symptoms related to the bradycardia, the dosage should be reduced.
In patients with peripheral circulatory disorders (Raynaud's disease or syndrome, intermittent claudication), beta blockers should be used with great caution as aggravation of these disorders may occur.
Metabolic/endocrine
Poentimol 10 mg tablets should be administered with caution to patients with impaired renal function or impaired hepatic function. Patients with liver or kidney insufficiency may need a lower dosage.
Poentimol 10 mg tablets may be used safely in diabetes. It may, however, interfere with the cardiovascular and possibly the metabolic responses to hypoglycaemia and, therefore, should be used with caution in diabetic patients treated with insulin or oral hypoglycaemic agents as well as patients subject to spontaneous hypoglycaemia.
Beta blockers may mask the symptoms of thyrotoxicosis or hypoglycaemia.
Other warnings
Patients with a history of psoriasis should take beta blockers only after careful consideration.
Beta blockers may increase sensitivity to allergens and the seriousness of anaphylactic reactions.
There have been reports of skin rashes and/or dry eyes associated with the use of beta-adrenergic blocking drugs. The reported incidence is rare and in most cases the symptoms have cleared when treatment was withdrawn. Discontinuance of the drug should be considered if any such reaction is not otherwise explicable. Cessation of therapy with the beta blocker should be gradual although withdrawal symptoms with timolol are infrequent.
The following statement will appear on the label of this product: `Do not take this medicine if you have a history of wheezing or asthma'.
').Intra-ocular pressure should be reassessed approximately four weeks after starting treatment because response to 'Poentimol' may take a few weeks to stabilise.
Provided that the intra-ocular pressure is maintained at satisfactory levels, many patients can then be placed on once-a-day therapy.
Transfer from other agents
When another topical beta-blocking agent is being used, discontinue its use after a full day of therapy and start treatment with 'Poentimol' the next day with one drop of 0.25% 'Poentimol' in each affected eye twice a day. The dosage may be increased to one drop of 0.5% solution in each affected eye twice a day, if the response is not adequate.
When transferring a patient from a single anti-glaucoma agent other than a topical beta-blocking agent, continue the agent and add one drop of 0.25% 'Poentimol' in each affected eye twice a day. On the following day, discontinue the previous agent completely, and continue with 'Poentimol'. If a higher dosage of 'Poentimol' is required, substitute one drop of 0.5% solution in each affected eye twice a day.
'Poentimol' Eye Drops Solution is also available as 'Poentimol' Unit dose: The Unit-dose Dispenser of 'Poentimol' is free from preservative and should be used for patients who may be sensitive to the preservative benzalkonium chloride, or when use of a preservative-free topical medication is advisable.
Use in the elderly: there has been wide experience with the use of timolol maleate in elderly patients. The dosage recommendations given above reflect the clinical data derived from this experience.
Paediatric Population:
Due to limited data, Timolol could only be recommended for use in primary congenital and primary juvenile glaucoma for a transitional period while a decision is made on a surgical approach and in case of failed surgery while awaiting further options.
Posology:
Clinicians should strongly evaluate the risks and benefits when considering medical therapy with Timolol in paediatric patients. A detailed paediatric history and examination to determine the presence of systemic abnormalities should precede the use of Timolol.
However, if benefit outweighs the risk, it is recommended to use the lowest active agent concentration available once daily. If IOP could not be sufficiently controlled, a careful up titration to a maximum of two drops daily per affected eye has to be considered. If applied twice daily, an interval of 12 hours should be preferred.
Furthermore the patients, especially neonates, should be closely observed after the first dose for one to two hours in the office and closely monitored for ocular and systemic side effects.
With regard to paediatric use, the 0.1% active agent concentration might already be sufficient.
Method of administration:
To limit potential adverse effects only one drop should be instilled per dosing time.
2.Duration of treatment:
“Paediatric Populationâ€). 4.3 ContraindicationsReactive airway disease including bronchial asthma or a history of bronchial asthma, severe chronic obstructive pulmonary disease; sinus bradycardia, sick sinus syndrome sino-atrial block, second- and third-degree atrioventricular block not controlled with pace-maker, overt cardiac failure, cardiogenic shock.
Hypersensitivity to the active substance or to any of the excipients.
4.4 Special warnings and precautions for useLike other topically applied ophthalmic agents, timolol is absorbed systemically. Due to beta-adrenergic component, timolol, the same types of cardiovascular, pulmonary and other adverse reactions seen with systemic beta-adrenergic blocking agents may occur. Incidence of systemic ADRs after topical ophthalmic administration is lower than for systemic administration. To reduce the systemic absorption, see 4.2.
Cardiac disorders:
In patients with cardiovascular diseases (e.g. coronary heart disease, Prinzmetal's angina and cardiac failure) and hypotension therapy with beta-blockers should be critically assessed and the therapy with other active substances should be considered. Patients with cardiovascular diseases should be watched for signs of deterioration of these diseases and of adverse reactions.
Due to its negative effect on conduction time, beta-blockers should only be given with caution to patients with first degree heart block.
Cardiac failure should be adequately controlled before beginning therapy with 'Poentimol'. Patients with a history of severe cardiac disease should be watched for signs of cardiac failure and have their pulse rates monitored.
Vascular disorders
Patients with severe peripheral circulatory disturbance/disorders (i.e. severe forms of Raynaud's disease or Raynaud's syndrome) should be treated with caution.
Respiratory disorders:
Respiratory reactions, including death due to bronchospasm in patients with asthma have been reported following administration of some ophthalmic beta-blockers.
'Poentimol' should be used with caution, in patients with mild/moderate chronic obstructive pulmonary disease (COPD) and only if the potential benefit outweighs the potential risk.
Hypoglycaemia/diabetes
Beta-blockers should be administered with caution in patients subject to spontaneous hypoglycaemia or to patients with labile diabetes, as beta-blockers may mask the signs and symptoms of acute hypoglycaemia.
Beta-blockers may also mask the signs of hyperthyroidism.
Corneal diseases
Ophthalmic beta-blockers may induce dryness of eyes. Patients with corneal diseases should be treated with caution.
Other beta-blocking agents
The effect on intra-ocular pressure or the known effects of systemic beta-blockade may be potentiated when timolol is given to the patients already receiving a systemic beta-blocking agent. The response of these patients should be closely observed. The use of two topical beta-adrenergic blocking agents is not recommended.
There have been reports of skin rashes and/or dry eyes associated with the use of beta-adrenoreceptor blocking drugs. The reported incidence is small and in most cases the symptoms have cleared when treatment was withdrawn. Discontinuation of the drug should be considered if any such reaction is not otherwise explicable. Cessation of therapy involving beta-blockade should be gradual.
Choroidal detachment
Choroidal detachment has been reported with administration of aqueous suppressant therapy (e.g. timolol, acetazolamide) after filtration procedures.
Surgical anaesthesia
Beta-blocking ophthalmological preparations may block systemic beta-agonist effects e.g. of epinephrine (adrenaline). The anaesthesiologist should be informed when the patient is receiving timolol.
'Poentimol' has been generally well tolerated in glaucoma patients wearing conventional hard contact lenses. 'Poentimol' has not been studied in patients wearing lenses made with material other than polymethylmethacrylate (PMMA), which is used to make hard contact lenses.
The Ocumeter® Dispenser of 'Poentimol' contains benzalkonium chloride as a preservative which may be deposited in soft contact lenses; therefore 'Poentimol' should not be used while wearing these lenses. The lenses should be removed before application of the drops and not reinserted earlier than 15 minutes after use.
In patients with angle-closure glaucoma, the immediate objective of treatment is to reopen the angle. This requires constricting the pupil with a miotic. 'Poentimol' has little or no effect on the pupil. When 'Poentimol' is used to reduce elevated intra-ocular pressure in angle-closure glaucoma it should be used with a miotic and not alone.
Patients should be advised that if they develop an intercurrent ocular condition (e.g. trauma, ocular surgery or infection), they should immediately seek their physician's advice concerning the continued use of the present multidose container (see 6.6 'Special precautions for disposal and other handling').
There have been reports of bacterial keratitis associated with the use of multiple dose containers of topical ophthalmic products. These containers had been inadvertently contaminated by patients who, in most cases, had a concurrent corneal disease or a disruption of the ocular epithelial surface.
Anaphylactic reactions
While taking beta-blockers, patients with a history of atopy or a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge with such allergens and, may be unresponsive to the usual dose of epinephrine (adrenaline) used to treat anaphylactic reactions.
Paediatric Population:
It is important to notify the parents of potential side effects so they can immediately discontinue the drug therapy. Signs to look for are, for example, coughing and wheezing.
Because of the possibility of apnoea and Cheyne-Stokes breathing, the drug should be used with extreme caution in neonates, infants and younger children. A portable apnoea monitor may also be helpful for neonates on Timolol.
Like other topically applied ophthalmic drugs, Poentimol Eye Drops is absorbed systemically.). It is important to notify the parents of potential side effects so they can immediately discontinue the drug therapy. Signs to look for are for example coughing and wheezing. Because of the possibility of apnoea and Cheyne-Stokes breathing, the drug should be used with extreme caution in neonates, infants and younger children. A portable apnoea monitor may also be helpful for neonates on Poentimol.
None known. When driving vehicles or operating machines it should be taken into account that occasionally dizziness or fatigue may occur.
Possible side effects such as dizziness, visual disturbances, refractive changes, diplopia, ptosis, frequent episodes of mild and transient blurred vision and fatigue may affect some patients' ability to drive or operate machinery.
There are currently no data available on the effects of Poentimol Eye Drops 0.5% on the ability to drive or use machinery. It has to be taken into account that dizziness, fatigue, transient ocular irritation, blurred vision and lacrimation may occur occasionally.
Posology
The lowest possible dosage should be given first in order to be able to identify cardiac decompensation or bronchial phenomena at an early stage; this is especially important in the elderly. Subsequent increases in dose should take place slowly, (e.g. once a week) under control or on the basis of clinical effect.
For angina:
The recommended dose range is 5 - 30 mg twice daily. The initial dose should be 5 mg twice daily, increasing the daily dose by 10 mg not more frequently than every 3 to 4 days to achieve optimum results.
Hypertension:
The recommended dose range is 10 - 60 mg daily. Most hypertensive patients will be controlled by 10 - 30 mg timolol which can be administered once daily or in two divided doses if preferred. Doses in excess of 30 mg daily should be given in two equally divided doses. The dose of Poentimol 10 mg tablets may need adjustment when used in conjunction with other antihypertensive drugs.
After myocardial infarction:
Start with 5 mg (½ tablet) twice daily for two days. If there are no adverse effects, increase dosage to 10 mg twice daily and maintain at this dose.
For the prophylactic treatment of migraine:
10 to 20 mg once daily or in two divided doses.
Dosage in the elderly:
Initiate treatment with lowest adult dose and thereafter adjust according to response.
Paediatric population:
The safety and efficacy of Poentimol 10 mg tablets in children has not been established. No data are available.
Method of administration
For oral use
Recommended therapy is one drop 0.25% solution in the affected eye twice a day.
When using nasolacrimal occlusion or closing the eyelids for 2 minutes, the systemic absorption is reduced. This may result in a decrease in systemic side effects and an increase in local activity.
If clinical response is not adequate, dosage may be changed to one drop 0.5% solution in each affected eye twice a day. If needed, 'Poentimol' may be used with other agent(s) for lowering intra-ocular pressure. The use of two topical beta-adrenergic blocking agents is not recommended (see 4.4 'Special warnings and precautions for use').
Intra-ocular pressure should be reassessed approximately four weeks after starting treatment because response to 'Poentimol' may take a few weeks to stabilise.
Provided that the intra-ocular pressure is maintained at satisfactory levels, many patients can then be placed on once-a-day therapy.
Transfer from other agents
When another topical beta-blocking agent is being used, discontinue its use after a full day of therapy and start treatment with 'Poentimol' the next day with one drop of 0.25% 'Poentimol' in each affected eye twice a day. The dosage may be increased to one drop of 0.5% solution in each affected eye twice a day, if the response is not adequate.
When transferring a patient from a single anti-glaucoma agent other than a topical beta-blocking agent, continue the agent and add one drop of 0.25% 'Poentimol' in each affected eye twice a day. On the following day, discontinue the previous agent completely, and continue with 'Poentimol'. If a higher dosage of 'Poentimol' is required, substitute one drop of 0.5% solution in each affected eye twice a day.
'Poentimol' Eye Drops Solution is also available as 'Poentimol' Unit dose: The Unit-dose Dispenser of 'Poentimol' is free from preservative and should be used for patients who may be sensitive to the preservative benzalkonium chloride, or when use of a preservative-free topical medication is advisable.
Use in the elderly: there has been wide experience with the use of timolol maleate in elderly patients. The dosage recommendations given above reflect the clinical data derived from this experience.
Paediatric Population:
Due to limited data, Timolol could only be recommended for use in primary congenital and primary juvenile glaucoma for a transitional period while a decision is made on a surgical approach and in case of failed surgery while awaiting further options.
Posology:
Clinicians should strongly evaluate the risks and benefits when considering medical therapy with Timolol in paediatric patients. A detailed paediatric history and examination to determine the presence of systemic abnormalities should precede the use of Timolol.
However, if benefit outweighs the risk, it is recommended to use the lowest active agent concentration available once daily. If IOP could not be sufficiently controlled, a careful up titration to a maximum of two drops daily per affected eye has to be considered. If applied twice daily, an interval of 12 hours should be preferred.
Furthermore the patients, especially neonates, should be closely observed after the first dose for one to two hours in the office and closely monitored for ocular and systemic side effects.
With regard to paediatric use, the 0.1% active agent concentration might already be sufficient.
Method of administration:
To limit potential adverse effects only one drop should be instilled per dosing time.
2.Duration of treatment:
“Paediatric Populationâ€).“Paediatric Populationâ€)â€.No special requirements.
').There have been reports of bacterial keratitis associated with the use of multiple dose containers of topical ophthalmic products. These containers had been inadvertently contaminated by patients who, in most cases, had a concurrent corneal disease or a disruption of the ocular epithelial surface.
Anaphylactic reactions
While taking beta-blockers, patients with a history of atopy or a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge with such allergens and, may be unresponsive to the usual dose of epinephrine (adrenaline) used to treat anaphylactic reactions.
Paediatric Population:
It is important to notify the parents of potential side effects so they can immediately discontinue the drug therapy. Signs to look for are, for example, coughing and wheezing.
Because of the possibility of apnoea and Cheyne-Stokes breathing, the drug should be used with extreme caution in neonates, infants and younger children. A portable apnoea monitor may also be helpful for neonates on Timolol.
4.5 Interaction with other medicinal products and other forms of interactionNo specific drug interaction studies have been performed with timolol maleate.
There is a potential for additive effects resulting in hypotension and/or marked bradycardia when ophthalmic beta-blockers solution is administered concomitantly with oral calcium-channel blockers, beta-adrenergic blocking agents, antiarrhythmics (including amiodarone), digitalis glycosides, rauwolfia alkaloids, parasympathomimetics, guanethidine.
Although 'Poentimol' alone has little or no effect on pupil size, mydriasis resulting from concomitant use of ophthalmic beta-blockers and epinephrine (adrenaline ) has been reported occasionally.
Potentiated systemic beta-blockade (e.g. decreased heart rate, depression) has been reported during combined treatment with CYP2D6 inhibitors (e.g. quinidine, fluoxetine, paroxetine) and timolol.
Oral beta-adrenergic blocking agents may exacerbate the rebound hypertension which can follow the withdrawal of clonidine.
Close observation of the patient is recommended when a beta-blocker is administered to patients receiving catecholamine-depleting drugs such as reserpine, because of possible additive effects and the production of hypotension and/or marked bradycardia, which may produce vertigo, syncope, or postural hypotension.
Oral calcium-channel antagonists may be used in combination with beta-adrenergic blocking agents when heart function is normal, but should be avoided in patients with impaired cardiac function.
The potential exists for hypotension, AV conduction disturbances and left ventricular failure to occur in patients receiving a beta-blocking agent when an oral calcium-channel blocker is added to the treatment regimen. The nature of any cardiovascular adverse effects tends to depend on the type of calcium-channel blocker used. Dihydropyridine derivatives, such as nifedipine, may lead to hypotension, whereas verapamil or diltiazem have a greater propensity to lead to AV conduction disturbances or left ventricular failure when used with a beta-blocker.
Intravenous calcium channel blockers should be used with caution in patients receiving beta-adrenergic blocking agents.
The concomitant use of beta-adrenergic blocking agents and digitalis with either diltiazem or verapamil may have additive effects in prolonging AV conduction time.
4.6 Fertility, pregnancy and lactationPregnancy
There are no adequate data for the use of timolol maleate in pregnant women. 'Poentimol' should not be used during pregnancy unless clearly necessary. To reduce the systemic absorption, see 4.2.
Epidemiological studies have not revealed malformative effects but show a risk for intra uterine growth retardation when beta-blockers are administered by the oral route. In addition, signs and symptoms of beta-blockade (e.g. bradycardia, hypotension, respiratory distress and hypoglycaemia) have been observed in the neonate when beta-blockers have been administered until delivery. If 'Poentimol' is administered until delivery, the neonate should be carefully monitored during the first days of life.
Lactation
Timolol is detectable in human milk. A decision for breastfeeding mothers, either to stop taking 'Poentimol' or stop nursing, should be based on the importance of the drug to the mother.
4.7 Effects on ability to drive and use machinesPossible side effects such as dizziness, visual disturbances, refractive changes, diplopia, ptosis, frequent episodes of mild and transient blurred vision and fatigue may affect some patients' ability to drive or operate machinery.
4.8 Undesirable effectsLike other topically applied ophthalmic drugs, timolol is absorbed into the systemic circulation. This may cause similar undesirable effects as seen with systemic beta-blocking agents. Incidence of systemic ADRs after topical ophthalmic administration is lower than for systemic administration. The following adverse reactions have been reported with ocular administration of this or other timolol maleate formulations, either in clinical trials or since the drug has been marketed. Additional side effects have been reported in clinical experiences with systemic timolol maleate, and may be considered potential effects of ophthalmic timolol maleate. Also listed are adverse reactions seen within the class of ophthalmic beta-blockers and may potentially occur with 'Poentimol'.
Eye disorders
ocular: signs and symptoms of ocular irritation, (e.g. burning, stinging, itching, tearing, redness), conjunctivitis, blepharitis, keratitis, dry eyes, decreased corneal sensitivity, blurred vision, corneal erosion. Visual disturbances, including refractive changes (due to withdrawal of miotic therapy in some cases), diplopia, ptosis and choroidal detachment following filtration surgery (see 4.4 'Special warnings and precautions for use').
Ear and labyrinth disorders:
ocular: tinnitus
Cardiac disorders
ocular: bradycardia, chest pain, arrhythmia, heart block, congestive heart failure, palpitations, cardiac arrest, cardiac failure, oedema;
systemic: atrioventricular block (second- or third-degree), sino-atrial block, pulmonary oedema, worsening of arterial insufficiency, worsening of angina pectoris, vasodilation.
Vascular disorders:
ocular: claudication, hypotension, Raynaud's phenomenon, cold hands and feet.
Respiratory, thoracic and mediastinal disorders:
ocular: bronchospasm (predominantly in patients with pre-existing bronchospastic disease), respiratory failure, dyspnoea, cough;
systemic: rales.
General disorders and administration site conditions:
ocular: asthenia, fatigue;
systemic: extremity pain, decreased exercise tolerance.
Skin and subcutaneous tissue disorders:
ocular: alopecia, psoriasiform rash or exacerbation of psoriasis, skin rash;
systemic: sweating, exfoliative dermatitis.
Immune system disorders:
ocular: systemic lupus erythematosus, pruritus;
systemic: signs and symptoms of allergic reactions including anaphylaxis, angioedema, urticaria, localised and generalised rash, anaphylactic reaction.
Psychiatric disorders:
ocular: depression, insomnia, nightmares, memory loss;
systemic: diminished concentration, increased dreaming.
Nervous system disorders
ocular: syncope, cerebrovascular accident, cerebral ischemia, headache, dizziness, increase in signs and symptoms of myasthenia gravis, paraesthesia;
systemic: vertigo, local weakness
Gastrointestinal disorders:
ocular: nausea, diarrhoea, dyspepsia, dry mouth dysgeusia, abdominal pain vomiting.
Reproductive system and breast disorders:
ocular: decreased libido, Peyronie's disease, sexual dysfunction such as impotence;
systemic: micturition difficulties.
Metabolism and nutrition disorders:
ocular: hypoglycaemia;
systemic: hyperglycaemia.
Musculoskeletal and connective tissue disorders:
ocular: myalgia;systemic: arthralgia.
Blood and lymphatic system disorders:
systemic: non-thrombocytopenic purpura.
4.9 OverdoseThere have been reports of inadvertent overdosage with 'Poentimol' resulting in systemic effects similar to those seen with systemic beta-adrenergic blocking agents such as dizziness, headache, shortness of breath, bradycardia, hypotension, bronchospasm, acute cardiac insufficiency and cardiac arrest (see 'Side effects').
If overdosage occurs, the following measures should be considered:
1. Gastric lavage, if ingested. Studies have shown that timolol does not dialyse readily.
2. Symptomatic bradycardia: atropine sulphate, 0.25 to 2 mg intravenously, should be used to induce vagal blockade. If bradycardia persists, intravenous isoprenaline hydrochloride should be administered cautiously. In refractory cases, the use of a cardiac pacemaker may be considered.
3. Hypotension: a sympathomimetic pressor agent such as dopamine, dobutamine or noradrenaline should be used. In refractory cases, the use of glucagon has been reported to be useful.
4. Bronchospasm: isoprenaline hydrochloride should be used. Additional therapy with aminophylline may be considered.
5. Acute cardiac failure: conventional therapy with digitalis, diuretics, and oxygen should be instituted immediately. In refractory cases, the use of intravenous aminophylline is suggested. This may be followed, if necessary, by glucagon, which has been reported useful.
6. Heart block (second- or third-degree): isoprenaline hydrochloride or a pacemaker should be used.
5. Pharmacological properties 5.1 Pharmacodynamic propertiesTimolol maleate is a non-selective beta-adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anaesthetic activity. Timolol maleate combines reversibly with the beta-adrenergic receptor, and this inhibits the usual biologic response that would occur with stimulation of that receptor. This specific competitive antagonism blocks stimulation of the beta-adrenergic stimulating (agonist) activity, whether these originate from an endogenous or exogenous source. Reversal of this blockade can be accomplished by increasing the concentration of the agonist which will restore the usual biological response.
Unlike miotics, 'Poentimol' reduces IOP with little or no effect on accommodation or pupil size. In patients with cataracts, the inability to see around lenticular opacities when the pupil is constricted is avoided. When changing patients from miotics to 'Poentimol' a refraction might be necessary when the effects of the miotic have passed.
Diminished response after prolonged therapy with 'Poentimol' has been reported in some patients.
Paediatric Population:
There is only very limited data available on the use of Timolol (0.25%, 0.5% twice daily one drop) in the paediatric population. In one small, double masked, randomized, published clinical study conducted for a treatment period up to 12 weeks on 105 children (n=71 on Timolol) aged 12 days - 5 years the data have shown to some extent evidence, that Timolol in the indication primary congenital and primary juvenile glaucoma is effective in short term treatment.
5.2 Pharmacokinetic propertiesThe onset of reduction in intra-ocular pressure can be detected within one-half hour after a single dose. The maximum effect occurs in one or two hours; significant lowering of IOP can be maintained for as long as 24 hours with a single dose.
Paediatric Population:
As already confirmed by adult data, 80% of each eye drop passes through the nasolacrimal system where it may be rapidly absorbed into the systemic circulation via the nasal mucosa, conjunctiva, nasolacrimal duct, oropharynx and gut, or the skin from tear overflow.
Due to the fact that the blood volume in children is smaller than that in adults a higher circulation concentration has to be taken into account. In addition, neonates have immature metabolic enzyme pathways and it may result in an increase in elimination half-life and potentiating adverse events.
Limited data show that plasma timolol levels in children after 0.25% greatly exceed those in adults after 0.5%, especially in infants and are presumed to increase the risk of side effects such as bronchospasm and bradycardia.
5.3 Preclinical safety dataNo adverse ocular effects were observed in rabbits and dogs administered 'Poentimol' topically in studies lasting one and two years, respectively. The oral LD50 of the drug is 1,190 and 900 mg/kg in female mice and female rats, respectively.
Carcinogenesis, mutagenesis, impairment of fertility
In a two-year oral study of timolol maleate in rats there was a statistically significant (p≤0.05) increase in the incidence of adrenal phaeochromocytomas in male rats administered 300 mg/kg/day (300 times the maximum recommended human oral dose). Similar differences were not observed in rats administered oral doses equivalent to 25 or 100 times the maximum recommended human oral dose.
In a lifetime oral study in mice, there were statistically significant (p≤0.05) increases in the incidence of benign and malignant pulmonary tumours, benign uterine polyps and mammary adenocarcinoma in female mice at 500 mg/kg/day (500 times the maximum recommended human dose), but not at 5 or 50 mg/kg/day. In a subsequent study in female mice, in which post-mortem examinations were limited to uterus and lungs, a statistically significant increase in the incidence of pulmonary tumours was again observed at 500 mg/kg/day.
The increased occurrence of mammary adenocarcinoma was associated with elevations in serum prolactin which occurred in female mice administered timolol at 500 mg/kg/day, but not at doses of 5 or 50 mg/kg/day. An increased incidence of mammary adenocarcinomas in rodents has been associated with administration of several other therapeutic agents which elevate serum prolactin, but no correlation between serum prolactin levels and mammary tumours has been established in man. Furthermore, in adult human female subjects who received oral dosages of up to 60 mg of timolol maleate, the maximum recommended human oral dosage, there were no clinically meaningful changes in serum prolactin.
Timolol maleate was devoid of mutagenic potential when evaluated in vivo (mouse) in the micronucleus test and cytogenetic assay (doses up to 800 mg/kg) and in vitro in a neoplastic cell transformation assay (up to 100 mcg/ml). In Ames tests the highest concentrations of timolol employed, 5,000 or 10,000 mcg/plate, were associated with statistically significant (p≤0.05) elevations of revertants observed with tester strain TA100 (in seven replicate assays) but not in the remaining three strains. In the assays with tester strain TA100, no consistent dose-response relationship was observed, nor did the ratio of test to control revertants reach 2. A ratio of 2 is usually considered the criterion for a positive Ames test.
Reproduction and fertility studies in rats showed no adverse effect on male or female fertility at doses up to 150 times the maximum recommended human oral dose.
6. Pharmaceutical particulars 6.1 List of excipientsDisodium phosphate dodecahydrate (may be replaced by equivalent amounts of the dihydrate or anhydrous )
Sodium dihydrogen phosphate dihydrate (may be replaced by equivalent amounts of monohydrate)
Sodium hydroxide
Benzalkonium chloride
Water for injections
6.2 IncompatibilitiesNone known.
6.3 Shelf life36 months
Discard 'Poentimol' Eye Drops Solution 28 days after opening the bottle.
6.4 Special precautions for storageDo not store above 25°C. Store the bottle in the outer carton in order to protect from light.
6.5 Nature and contents of containerThe OCUMETER Plus ophthalmic dispenser consists of a translucent high-density polyethylene container with a sealed dropper tip, a flexible fluted side area, which is depressed to dispense the drops, and a two-piece cap assembly. The two-piece cap mechanism punctures the sealed dropper tip upon initial use, then locks together to provide a single cap during the usage period. Tamper evidence is provided by two perforated tabs on the container label extending on to the cap. The OCUMETER Plus ophthalmic dispenser contains 5 ml of solution.
6.6 Special precautions for disposal and other handlingPatients should be instructed to avoid allowing the tip of the dispensing container to contact the eye or surrounding structures.
Patients should also be instructed that ocular solutions, if handled improperly, can become contaminated by common bacteria known to cause ocular infections. Serious damage to the eye and subsequent loss of vision may result from using contaminated solutions.
