Overdosage with the 4-aminoquinolines is dangerous particularly in infants, as little as 1-2g having proved fatal.
The symptoms of overdosage may include headache, visual disturbances, cardiovascular collapse, convulsions, hypokalaemia, and rhythm and conduction disorders, followed by sudden and early respiratory and cardiac arrest. Since these effects may appear soon after taking a massive dose, treatment should be prompt and symptomatic. The stomach should be immediately evacuated, either by emesis or by gastric lavage. Activated charcoal in a dose at least five times of the overdose may inhibit further absorption if introduced into the stomach by tube following lavage and within 30 minutes of ingestion of the overdose.
Consideration should be given to administration of parenteral diazepam in cases of overdosage; it has been shown to be beneficial in reversing chloroquine cardiotoxicity.
Respiratory support and shock management should be instituted as necessary.
3 years
No incompatibilities are known.
Lactose monohydrate, maize starch, magnesium stearate, polyvidone, Opadry OY-L-28900 (containing hypromellose, macrogol 4000, titanium dioxide (E171), lactose.)
- Ocular effects:
Retinopathy with changes in pigmentation and visual field defects can occur, but appears to be uncommon if the recommended daily dose is not exceeded. In its early form it appears reversible on discontinuation of Plaquenil. If allowed to develop, there may be a risk of progression even after treatment withdrawal.
Patients with retinal changes may be asymptomatic initially, or may have scotomatous vision with paracentral, pericentral ring types, temporal scotomas and abnormal colour vision.
Corneal changes including oedema and opacities have been reported. They are either symptomless or may cause disturbances such as haloes, blurring of vision or photophobia. They may be transient and are reversible on stopping treatment.
Blurring of vision due to a disturbance of accommodation which is dose dependent and reversible may also occur.
- Dermatologic effects:
Skin rashes sometimes occur; pruritus, pigmentary changes in skin and mucous membranes, bleaching of hair and alopecia have also been reported. These usually resolve readily on stopping treatment.
Bullous eruptions including very rare cases of erythema multiforme and Stevens-Johnson syndrome, photosensitivity and isolated cases of exfoliative dermatitis have been reported. Very rare cases of acute generalised exanthematous pustulosis (AGEP) has to be distinguished from psoriasis, although hydroxychloroquine may precipitate attacks of psoriasis. It may be associated with fever and hyperleukocytosis. Outcome is usually favourable after drug withdrawal.
- Gastrointestinal effects:
Gastrointestinal disturbances such as nausea, diarrhoea, anorexia, abdominal pain and, rarely, vomiting may occur. These symptoms usually resolve immediately on reducing the dose or on stopping treatment.
- CNS effects:
Less frequently, dizziness, vertigo, tinnitus, hearing loss, headache, nervousness, emotional lability, toxic psychosis and convulsions have been reported with this class of drugs.
- Neuromuscular effects:
Skeletal muscle myopathy or neuromyopathy leading to progressive weakness and atrophy of proximal muscle groups have been noted. Myopathy may be reversible after drug discontinuation, but recovery may take many months.
Associated mild sensory changes, depression of tendon reflexes and abnormal nerve conduction may be observed.
- Cardio-vascular effects:
Cardiomyopathy has been rarely reported.
Chronic toxicity should be suspected when conduction disorders (bundle branch block/atrioventricular heart block) as well as biventricular hypertrophy are found. Drug withdrawal may lead to recovery.
- Hematologic effects:
Rarely, there have been reports of bone-marrow depression. Blood disorders such as anaemia, aplastic anaemia, agranulocytosis, a decrease in white blood cells and thrombocytopenia have been reported.
Hydroxychloroquine may precipitate or exacerbate porphyria.
- Liver effects:
Isolated cases of abnormal liver function tests have been reported; rare cases of fulminant hepatic failure have also been reported.
- Allergic reactions:
Urticaria, angioedema and bronchospasm have been reported.
- Metabolism and nutrition disorders:
Hypoglycaemia. Frequency: unknown.
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
There are no preclinical safety data of relevance to the prescriber, which are additional to that already included in other sections of the SPC.
Adults
Treatment of rheumatoid arthritis, discoid and systemic lupus erythematosus, and dermatological conditions caused or aggravated by sunlight.
Paediatric population
Treatment of juvenile idiopathic arthritis (in combination with other therapies), discoid and systemic lupus erythematosus.
Antimalarial agents like chloroquine and hydroxychloroquine have several pharmacological actions which may be involved in their therapeutic effect in the treatment of rheumatic disease, but the role of each is not known. These include interaction with sulphydryl groups, interference with enzyme activity (including phospholipase, NADH - cytochrome C reductase, cholinesterase, proteases and hydrolases), DNA binding, stabilisation of lysosomal membranes, inhibition of prostaglandin formation, inhibition of polymorphonuclear cell chemotaxis and phagocytosis, possible interference with interleukin 1 production from monocytes and inhibition of neutrophil superoxide release.
Hydroxychloroquine has actions, pharmacokinetics and metabolism similar to those of chloroquine. Following oral administration, hydroxychloroquine is rapidly and almost completely absorbed. In one study, mean peak plasma hydroxychloroquine concentrations following a single dose of 400mg in healthy subjects ranged from 53-208ng/ml with a mean of 105ng/ml. The mean time to peak plasma concentration was 1.83 hours. The mean plasma elimination half-life varied, depending on the post-administration period, as follows: 5.9 hours at Cmax-10 hours), 26.1 hours (at 10-48 hours) and 299 hours (at 48-504 hours). The parent compound and metabolites are widely distributed in the body and elimination is mainly via the urine, where 3% of the administered dose was recovered over 24 hours in one study.
2 January 2014
Aventis Pharma Limited
One Onslow Street
Guildford
Surrey
GU1 4YS
UK
or trading as:
sanofi-aventis or Sanofi
One Onslow Street
Guildford
Surrey
GU1 4YS
UK
Store below 25°C.
Amber glass bottles with a tin plate screw cap containing 100 tablets. HDPE bottle with LDPE cap containing 56 tablets. 250µm clear PVC/20µm aluminium foil blister pack containing 56 or 60 tablets.
PL 04425/0621
General
- The occurrence of retinopathy is very uncommon if the recommended daily dose is not exceeded. The administration of doses in excess of the recommended maximum is likely to increase the risk of retinopathy, and accelerate its onset.
- All patients should have an ophthalmological examination before initiating treatment with Plaquenil. Thereafter, ophthalmological examinations must be repeated at least every 12 months.
The examination should include testing visual acuity, careful ophthalmoscopy, fundoscopy, central visual field testing with a red target, and colour vision.
This examination should be more frequent and adapted to the patient in the following situations:
- daily dosage exceeds 6.5mg/kg lean body weight. Absolute body weight used as a guide to dosage could result in an overdosage in the obese.
- renal insufficiency
- visual acuity below 6/8
- age above 65 years
- cumulative dose more than 200 g.
Plaquenil should be discontinued immediately in any patient who develops a pigmentary abnormality, visual field defect, or any other abnormality not explainable by difficulty in accommodation or presence of corneal opacities. Patients should continue to be observed for possible progression of the changes.
Patients should be advised to stop taking the drug immediately and seek the advice of their prescribing doctor if any disturbances of vision are noted, including abnormal colour vision.
Plaquenil should be used with caution in patients taking medicines which may cause adverse ocular or skin reactions. Caution should also be applied when it is used in the following:
- patients with hepatic or renal disease, and in those taking drugs known to affect those organs. Estimation of plasma hydroxychloroquine levels should be undertaken in patients with severely compromised renal or hepatic function and dosage adjusted accordingly.
- patients with severe gastrointestinal, neurological or blood disorders.
Although the risk of bone marrow depression is low, periodic blood counts are advisable as anaemia, aplastic anaemia, agranulocytosis, a decrease in white blood cells, and thrombocytopenia have been reported. Plaquenil should be discontinued if abnormalities develop.
Caution is also advised in patients with a sensitivity to quinine, those with glucose-6-phosphate dehydrogenase deficiency, those with porphyria cutanea tarda which can be exacerbated by hydroxychloroquine and in patients with psoriasis since it appears to increase the risk of skin reactions.
Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
Small children are particularly sensitive to the toxic effects of 4-aminoquinolines; therefore patients should be warned to keep Plaquenil out of the reach of children.
All patients on long-term therapy should undergo periodic examination of skeletal muscle function and tendon reflexes. If weakness occurs, the drug should be withdrawn.
Hydroxychloroquine has been shown to cause severe hypoglycaemia including loss of consciousness that could be life threatening in patients treated with and without antidiabetic medications. Patients treated with hydroxychloroquine should be warned about the risk of hypoglycaemia and the associated clinical signs and symptoms. Patients presenting with clinical symptoms suggestive of hypoglycaemia during treatment with hydroxychloroquine should have their blood glucose level checked and treatment reviewed as necessary.
Impaired visual accommodation soon after the start of treatment has been reported and patients should be warned regarding driving or operating machinery. If the condition is not self-limiting, it will resolve on reducing the dose or stopping treatment.
Adults (including the elderly)
The minimum effective dose should be employed. This dose should not exceed 6.5mg/kg/day (calculated from ideal body weight and not actual body weight) and will be either 200mg or 400mg per day.
In patients able to receive 400mg daily:
Initially 400mg daily in divided doses. The dose can be reduced to 200mg when no further improvement is evident. The maintenance dose should be increased to 400mg daily if the response lessens.
Paediatric population
The minimum effective dose should be employed and should not exceed 6.5mg/kg/day based on ideal body weight. The 200mg tablet is therefore not suitable for use in children with an ideal body weight of less than 31kg.
Each dose should be taken with a meal or glass of milk.
Hydroxychloroquine is cumulative in action and will require several weeks to exert its beneficial effects, whereas minor side effects may occur relatively early. For rheumatic disease treatment should be discontinued if there is no improvement by 6 months. In light-sensitive diseases, treatment should only be given during periods of maximum exposure to light.
The tablets are for oral administration.
None.
27 August 1997
