Intravitreal toxicity of cotrimoxazole

We investigated the intravitreal toxicity of cotrimoxazole (trimethoprim 80 mg and sulfamethoxazole 400 mg/5 ml of injection fluid) in albino rabbits. Eyes injected intravitreally with 1600 micrograms/0.1 cc (reported in trimethoprim concentration) exhibited no histologic or abnormal electroretinographic responses after 14 days. A vitrectomy infusion solution containing 32 micrograms/ml (reported in trimethoprim concentration) produced no toxicity, as demonstrated either by electroretinography or histology. Cotrimoxazole appears to be well-tolerated in rabbit eyes when administered by both intravitreal injection and vitrectomy infusion solution.