Experimental assessment of the protective activity of diazepam on the acute toxicity of chloroquine.

The dose of diazepam that reduces the mortality rate of acute intoxications with chloroquine was determined: The oral LD 50 of chloroquine (330 mg/kg) was administered and immediately thereafter diazepam was injected intraperitoneally to male and female rats at dose levels of 2.5, 7.5, 20, 55, and 148 mg/kg. An untreated group served as control. A significant decrease of the mortality rate was observed at the dose levels 7.5, 20, and 55 mg/kg with optimal effect at 20 mg/kg. This mortality rate was analysed by analysis of variance. The occurrence of two types of symptoms: convulsions and respiratory disturbances was analysed by the chi square method.