Immune system disorders:
Hypersensitivity reactions (see also Skin and subcutaneous tissue disorders).
Metabolism and nutrition disorders:
Metabolic disturbances such as hypokalaemia, hypophosphataemia, and hyponatraemia may occur.
Nervous system/Psychiatric disorders:
Headache, insomnia, confusion, restlessness, hyperventilation, anxiety, vertigo/dizziness, tremor. Higher doses may lead to maniacal behaviour, delirium and convulsions.
Eye disorders:
Visual disturbances.
Cardiac disorders:
Palpitations, tachycardia, cardiac arrhythmias, hypotension.
Gastrointestinal disorders:
Nausea, vomiting, abdominal pain, diarrhoea, gastro-oesophageal reflux, gastrointestinal bleeding.
Skin and subcutaneous tissue disorders:
Rash, maculo-papular rash, erythema, pruritus, urticaria, exfoliative dermatitis.
General/Administration site reactions:
Higher doses may result in hyperthermia and extreme thirst.
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.
4.9 OverdosePhyllocontin Continuse has a narrow therapeutic index. Theophylline toxicity is most likely to occur when serum concentrations exceed 20 micrograms/ml and becomes progressively more severe at higher serum concentrations.
Fatalities in adults have occurred during IV Phyllocontin Continuse administration in large doses in patients with renal, hepatic or cardiovascular complications or where the injection has been given rapidly.
Symptoms
Tachycardia, in the absence of hypoxia, fever or administration of sympathomimetic drugs, may be an indication of theophylline toxicity.
Gastro-intestinal symptoms:
Anorexia, nausea, vomiting, diarrhoea, and haematemesis.
Neurological symptoms:
Restlessness, insomnia, irritability, headache, agitation, hallucinations, extreme thirst, slight fever, dilated pupils, and tinnitus. Seizures may occur even without preceding symptoms of toxicity and often result in death. Coma may develop in very severe cases.
Cardiovascular symptoms:
Palpitations, arrhythmias, hypotension, supraventricular and ventricular arrhythmias may occur.
Metabolic symptoms:
Hypokalaemia can develop rapidly and may be severe. Hyperglycaemia, albuminuria, hyperthermia, hypomagnesaemia, hypophosphataemia, hypercalcaemia, respiratory alkalosis and metabolic acidosis may also occur. Rhabdomyolysis may also occur.
Treatment
Treatment of overdosage is supportive and symptomatic. Serum theophylline and potassium levels should be monitored. Repeated oral administration of activated charcoal enhances the elimination of theophylline from the body even after intravenous administration. Aggressive antiemetic therapy may be required to allow administration and retention of activated charcoal.
Seizures may be treated with IV diazepam 0.1-0.3mg/kg up to 10mg. Restoration of fluid and electrolytes balance is necessary. Hypokalaemia should be corrected by intravenous infusion of potassium chloride. Sedation with diazepam may be required in agitated patients.
Propranolol may be administered intravenously to reverse extreme tachycardia, hypokalaemia and hyperglycaemia provided the patient does not suffer from asthma.
In general, theophylline is metabolised rapidly and haemodialysis is not warranted. In patients with congestive heart failure or liver disease, haemodialysis may increase theophylline clearance by as much as 2-fold.
Charcoal haemoperfusion should be considered if:
- Ileus/ intestinal obstruction prevents administration of multiple dose activated charcoal.
- Plasma theophylline concentration > 80mg/L (acute) or > 60mg/L (chronic). In infants under 6 months of age or the elderly, charcoal haemoperfusion should be considered at theophylline concentrations >40 mg/L. Clinical features rather than theophylline concentration are the best guide for treatment.
Phyllocontin Continuse injection should not be used in patients hypersensitive to ethylenediamine or those allergic to the theophyllines, caffeine or theobromine.
Phyllocontin Continuse should not be administered concomitantly with other xanthine drugs. When therapeutic doses of Phyllocontin Continuse and/or theophylline are administered simultaneously by more that one route or in more than one preparation, the hazard of serious toxicity is increased.
The use of Phyllocontin Continuse IV in children under 6 months of age is not recommended.
The use of Phyllocontin Continuse is contraindicated in patients with acute porphyria.
Phyllocontin Continuse injection is not stable in solutions having a pH of substantially less than 8, however, the drug appears to be relatively stable in large volume parenteral solutions over a wide pH range (3.5-8.6) if Phyllocontin Continuse concentrations do not exceed 40mg per ml. The activity of alkali-sensitive drugs will be reduced by Phyllocontin Continuse, these drugs should not be added to IV fluids containing Phyllocontin Continuse.
Adverse events are usually a consequence of gastrointestinal irritation, stimulation of the central nervous system and effects on the cardiovascular system. Hypotension, arrhythmias and convulsions may follow intravenous injection, particularly if the injection is too rapid, and sudden deaths have been reported. Severe toxicity may occur without preceding milder symptoms (see also
No further information other than that which is included in the Summary of Product Characteristics.
Disease of the cardiovascular system (e.g. an adjunct in the treatment of pulmonary oedema or paroxysmal nocturnal dyspnoea caused by left ventricular heart failure), reversible airways obstruction including status asthmaticus and acute bronchospasm.
Phyllocontin Continuse is a soluble derivative of theophylline and is given for its theophylline activity. Phyllocontin Continuse relaxes smooth muscle and relieves bronchial spasm. It stimulates the myocardium and reduces venous pressure in congestive heart failure, leading to a marked increase in cardiac output. It has stimulant effect on respiration, and also a diuretic action of short duration.
None stated.
Intravenous Phyllocontin Continuse must be administered very slowly to prevent dangerous central nervous system and cardiovascular side-effects due to direct stimulating effect of Phyllocontin Continuse.
Phyllocontin Continuse has a narrow therapeutic index and serum levels should be monitored regularly, particularly during initiation of therapy.
Phyllocontin Continuse injection should be administered cautiously to patients over 55 years of age.
Children are particularly susceptible to the effects of theophylline and care is required when administrating Phyllocontin Continuse to children. There have been reports of seizures in children with theophylline plasma levels within the accepted therapeutic range. Alternative treatment should be considered in patients with a history of seizure activity and, if Phyllocontin Continuse Injection is used in such patients, they should be carefully observed for possible signs of central stimulation.
Caution is also advised in patients undergoing influenza immunisation or who have active influenza infection or acute febrile illness.
Phyllocontin Continuse should be given with caution to patients with cardiac failure, chronic obstructive pulmonary disease, renal or hepatic dysfunction and in chronic alcoholism since clearance of Phyllocontin Continuse is decreased.
Theophylline clearance may be increased in smokers and in those regularly exposed to tobacco smoke.
During regular therapy serum potassium levels must be monitored. This is essential during combination therapy with beta2-agonists, corticosteroids or diuretics, or in the presence of hypoxia.
Phyllocontin Continuse should be used with caution in patients with peptic ulcer, hyperthyroidism, glaucoma, diabetes mellitus, severe hypoxaemia, hypertension, compromised cardiac or circulatory function and epilepsy, as these conditions may be exacerbated.
Phyllocontin Continuse should not be administered concurrently with other xanthine medications.
None known.
Phyllocontin Continuse Injection BP may be given by slow intravenous injection or intravenous infusion in glucose injection or sodium chloride injection.
Phyllocontin Continuse has a narrow therapeutic index, therefore cautious dosage determination is essential. Therapeutic serum concentrations of theophylline are considered to range from 10 to 20 mcg/ml and levels greater than 20 mcg/ml are often associated with toxic effects. A range of 5 to 15 mcg/ml may be effective, and associated with fewer adverse effects.
The dosage should be titrated for each individual and adjusted with caution. Serum theophylline levels should be monitored to ensure that they remain within the therapeutic range. During therapy, patients should be monitored carefully for signs of toxicity.
Elimination of theophylline in children younger than 6 months of age, especially in neonates, appears to be reduced. Because of this variation in metabolism the use of Phyllocontin Continuse injection in children under 6 months of age is not recommended.
Use in patients NOT currently receiving theophylline preparations
To minimise adverse effects, IV Phyllocontin Continuse should be administered slowly, at a rate not exceeding 25mg Phyllocontin Continuse per minute, up to a dose of 250-500mg (5mg/kg). If patients experience acute adverse effects while loading doses are being infused, the infusion may be stopped for 5-10 minutes or administered at a slower rate.
Approximate IV Phyllocontin Continuse Maintenance Doses
n.b. The use of Phyllocontin Continuse IV in children under 6 months of age is not recommended.
| Group | Maintenance Dose |
| Children 6 months to 9 years of age | 1mg/kg/hour |
| Children 10-16 years of age and young adult smokers | 0.8mg/kg/hour |
| Otherwise healthy non-smoking adults | 0.5mg/kg/hour |
| Elderly patients | 0.3mg/kg/hour |
Use in patients currently receiving theophylline preparations
In patients who are currently receiving theophylline preparations, the time, route of administration and dosage form of the patient's last dose should be determined where possible and considered in determining a loading dose. Loading doses are based on the expectation that 0.5mg/kg (lean body weight) of theophylline will result in a 1 microgram/ml increase in serum theophylline concentration. Therefore, in patients currently receiving theophylline preparations, the loading dose should be deferred until a serum theophylline concentration can be attained or the clinician must carefully select a dose based on the potential benefits and risks.
Subsequently, the approximate IV Phyllocontin Continuse maintenance doses described above may be considered.
Use as directed by a physician.
