Indication

Rheumatoid arthritis, Malaria, Systemic lupus erythematosus, SLE, Amoebiasis

Administration

Should be taken with food.

Adult Dose

Malaria\r\nPrevention: 500 mg (300 mg base) PO once/week\r\n\r\nNon-chloroquine-resistant\r\n1 g (600 mg base) PO, THEN\r\n500 mg (300 mg base) PO 6-8 hours later, THEN\r\n500 mg (300 mg base) PO at 24 hours & 48 hours after initial dose\r\n\r\nAmebiasis, Extraintestinal\r\n1 g (600 mg base) PO qDay for 2 days, THEN\r\n500 mg (300 mg base) qDay for 14-21 days

Child Dose

Malaria\r\nProphylaxis: 5 mg/kg PO q1Week \r\n\r\nTreatment\r\n1st dose: 10 mg/kg PO x1 dose\r\n6 hours after 1st dose: 5 mg/kg PO qDay x2 days

Renal Dose

Renal impairment: May need to reduce dose in prolonged treatment.

Contraindication

Hypersensitivity, known or suspected resistant P. falciparum infection, porphyria, retinal damage, concurrent hepatotoxic drugs.

Mode of Action

Chloroquine is used for malarial prophylaxis (as a suppressive) and in managing acute attacks of malaria. It is highly active against erythrocytic forms of P. vivax, P. malariae and P. falciparum. It influences Hb digestion by increasing intravesicular pH in malaria parasite cells and interferes with the nucleoprotein synthesis of the patient. It is also effective in extra intestinal amoebiasis. In RA chloroquine and more effectively hydroxychloroquine have a disease-modifying effect.

Precaution

Psoriasis, diseases of the haematopoietic or CNS systems, myasthenia gravis, hepatic or renal impairment, G6PD deficiency, epilepsy, childn. Pregnancy and lactation. Slow infusion is used upon IV admin to prevent cardiotoxicity.\r\n\r\nLactation: enters breast milk/not recommended

Side Effect

Retinopathy, hair loss, photosensitivity, tinnitus, myopathy (long-term therapy). Diarrhea, Loss of appetite, Nausea, Stomach cramps, Vomiting, Psychosis, seizures, leucopenia and rarely aplastic anaemia, hepatitis, GI upsets, dizziness, hypokalaemia, headache, pruritus, urticaria, difficulty in visual accommodation.\r\n\r\nPotentially Fatal: Cardiac and respiratory arrest, CV collapse, convulsions, coma.

Pregnancy Category Note

Pregnancy\r\nThere are no adequate and well-controlled studies evaluating the safety and efficacy of chloroquine in pregnant women; usage during pregnancy should be avoided except in prophylaxis or treatment of malaria when benefit outweighs potential risk to fetus\r\n\r\nLactation\r\nBecause of the potential for serious adverse reactions in nursing infants from chloroquine, a decision should be made whether to discontinue nursing or to discontinue drug, taking into account potential clinical benefit of drug to mother

Interaction

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.\r\n\r\nPotentially Fatal: Increased risks of inducing ventricular arrhythmias with halofantrine or other arrhythmogenic drugs eg, amiodarone. Increased risk of convulsions with mefloquine. Antacids reduce absorption of chloroquine hence admin should be separated by 4 hrs. Rarely Stevens-Johnson syndrome, when administered with pyrimethamine/sulphadoxine. Increased toxicity with quinacrine