Toxicity of intravitreal nimodipine in the rabbit

Purpose: Many studies have demonstrated a neuroprotective effect of nimodipine. As part of an ongoing multiphase study to evaluate nimodipine for potential use in treating eye disease, we investigated the toxicity of intravitreal injection of nimodipine in the rabbits. Methods: Six New Zealand white rabbits received an intravitreal injection of 3 mg of nimodipine in Healon in the left eye, and the same amount of Healon only in the right eye. Scotopic and photopic electroretinograms (ERG) and clinical examinations (slit lamp and dilated fundus) were performed pre-operatively, and on days 1, 4, 8, 14, 21, and 30 post-operatively. Results: Clinical examination revealed no toxicity directly related to nimodipine. Superotemporal cataracts were noticed in 4 right eyes and 4 left eyes of the study animals, and appeared to be secondary to trauma. ERG wave analysis did not show any evidence of drug-related retinal dysfunction. Conclusions: Nimodipine appears to be well tolerated following intravitreal injection. Cataract formation was most likely not due to nimodipine since it occurred in control eyes. Further phases of this study will focus on applying intravitreal nimodipine to acute and chronic ocular pathologies.