Adverse reactions to chloroquine and amodiaquine as used for malaria prophylaxis: a review of the literature

Abstract

This paper reviews the published material on adverse reactions to chloroquine (CQ) and amodiaquine (ADQ) as used for anti-malarial chemophrophylaxis. Dermatologic reactions, including pruritus and photosensitivity, appear to be rather common. Ophthalmologic reactions include difficulty in visual accommodation, corneal deposits, and retinopathy, the last a serious condition that is reversible in its early stage by drug withdrawal, and that generally will not occur with less than four years of weekly CQ use. Neuromyopathy is a rare and serious reaction that may develop idiosyncratically after a small cumulative dose; it, too, is reversible by drug withdrawal. Seizures, syndromes of involuntary movements, psychosis, and ototoxicity have been reported occasionally. Fatal toxic overdoses may occur, especially following accidental ingestion by children. ADQ should not be used for anti-malarial prophylaxis because of associated agranulocytosis. Rabies vaccine given intradermally is less effective for pre-exposure prophylaxis while the patient is taking CQ. Care should be taken when prescribing prophylactic CQ to patients with heart block. In spite of its adverse effects, however, CQ is generally an extremely safe drug. Cq prophylaxis is recommended for pregnant women in CQ-sensitive malarial areas.