Chloroquine diphosphate

Human toxicity Chloroquine is a potentially fatal poisoning, often characterized by rapid deterioration. Features of toxicity may develop within 1 to 2 h, and death may occur abruptly, generally from myocardial depression and dysrhythmia. Symptoms at an acute overdose are as following: hyperexcitability, agitation, seizures, cerebral edema, ventricular dysrhythmia, hypotension, shock, cardiac arrest, respiratory arrest, coma, and death. Among gastrointestinal symptoms, nausea, vomiting, diarrhea, and hemorrhagic gastritis have been reported with therapeutic use or overdose [1]. Therapeutic oral dose of chloroquine for malaria is 500 mg in once weekly dose, for 3 to 4 weeks, or in daily doses of 250 mg for rheumatoid disease [2]. As little as 2-3 g of the chloroquine may be fatal in an adult. The most commonly reported lethal dose for adults is 3 to 4 g. A minimum lethal dose in man is estimated at 30 to 50 mg/kg. Therapeutic plasma levels for chloroquine are in the range from 0.02 to 0.04 mg/l to 0.15 to 0.25 mg/l [1]. Chloroquine toxicity is dose dependent. When doses less than 2 g were ingested, no clinical symptoms were registered, and serum chloroquine level was less than 2.5 mg/l. At higher doses ingested, from 2 to 4 g, serum chloroquine level was in the range of 2.5 to 5.0 mg/l; when ingested dose was greater than 4 g, serum chloroquine level was greater than 5 mg/l [1]. The average plasma chloroquine concentrations in 5 persons who ingested 3-20 g of the drug was 10 mg/l (range 3-16 mg/l; post-mortem specimens){reviewed in [2]}. The mean clinically measured acute lethal serum concentration of chloroquine, based on data from several handbooks, was 11 mg/l [3].