Effect of chronic oral administration of chloroquine on the histology of the heart in Wistar rats

The effect of chronic oral administration of chloroquine, an antimalarial and antirheumatic drug on the histologyof the heart in Wistar rats was investigated. Ten Wistar rats were randomly grouped into two, control and treated.The treated group rats were administered 20mg/kg body wt, weekly of chloroquine for 4 weeks while the controlgroup rats were given distilled water for 4 weeks. On day 29 of the experiment, the rats were weighed andsacrificed. The hearts were carefully dissected out and quickly fixed in 10% formal saline for routine histologicalstudy after H&E method. The histological findings indicated that the treated sections of the hearts showedmoderate hypertrophy of the cardiomyocytes when compared with the control. Thus, our result suggests thatthough chloroquine may be a widely used antimalarial and antirheumatic drug, its chronic administration mayresult in cardiotoxicity. Therefore, it is recommended that the drug be prescribed with caution in patients withcardiac abnormality, such as cardiomyopathy and further studies to corroborate this observation should becarried.