Description

Concomitant therapy with phenylbutazone predisposes to dermatitis, antagonises effect of neostigmine and pyridostigmine, reduces bioavailability of ampicillin. Cimetidine inhibits metabolism of chloroquine raising plasma levels.

Choroquine is well tolerated at the standard dosage regimens, side effects such as headache and gastrointestinal disturbances which may occur are not of a serious nature. Where prolonged high dose is required side effects can be of greater severity and patients may develop skin eruptions, occasional depigmentation or loss of hair, difficulty in accommodation, blurring of vision. Corneal opacities disappear completely when the drug is stopped. Rarely thrombocytopenia, agranulocytosis and aplastic anemia have been reported. The most serious toxic hazard of prolonged therapy with doses is the occasional development of irreversible retinal damage. For this reason considerable caution is needed in the use of choroquine for long-term high dosage therapy and such use should only be considered when no other drug is available. Defects in visual accommodation may occur on first taking choloquine and patients should be warned regarding driving or operating machinery.

As with all other drugs, the use of choroquine during pregnancy should be avoided if possible, unless in the case of threatening infections, in the judgment of the physician, when the potential benefit outweighs the risk.

Caution is necessary when giving choroquine to patients with porphyria who also have hepatic dysfunction or cirrhosis as the drug may precipitate severe constitutional symptoms and an increase in the amount of porphyrins excreted in the urine. This reaction is especially apparent in alcoholics. Patients receiving choloquine continuously at higher dose levels for a period longer than 12 months or at weekly intervals for a period of more than 3 years as prophylactic against malaria (or the consumption exceeds 1.6 g/Kg) should undergo ophthalmic examination at three months interval.

Amoebic hepatitis: Four tablets daily for two days followed by one tablet twice daily for two or three weeks. Lupus erythomatosus: One tablet twice daily for one to two weeks followed by a maintenance dose of one tablet daily.

Anti-malarial drugs

Store at room temperature in a dry place, away from light.