[Subacute chloroquine overdosage].

Owing to a misunderstanding a 26-year-old man took for malaria prevention 2 tablets (1.0 g) chloroquine daily instead of the recommended dose of two tablets weekly. After 2 weeks he developed vertigo, generalized weakness and, after sun-bathing, severe bullous light reaction. After 4 weeks generalized hair depigmentation occurred. Two weeks later abnormal accommodation and double vision set in so that he lost distant and near vision. All these signs disappeared after the drug was discontinued (vertigo, weakness and abnormal accommodation within 2 weeks; hair regrew in normal colour after 8 weeks). This case shows the whole spectrum of subacute chloroquine overdosage.