Myopathy in rats treated with chlorphentermine or iprindole.

Muscular lesions were induced in rats by prolonged administration of chlorphentermine and iprindole. The alterations consisted of longitudinal fibre splitting, fibre degeneration and necrosis, and of formation of dense cytoplasmic inclusions and large cytoplasmic vacuoles. The soleus muscle was more severely affected than were extensor digitorum longus (EDL), gastrocnemius, and lumbrical muscles. This myopathy closely resembles that induced by chloroquine. The pathogenesis of the muscular lesions, and causal relationship between myotoxic and lipidosis-inducing effects of the drugs under study remain to be elucidated.