Evaluation of ocular toxicity of two beta blocking drugs, carteolol and practolol, in beagle dogs.

The ocular effects of two beta blocking drugs, carteolol and practolol, were assessed in beagle dogs. Practolol-treated dogs showed a tear flow reduction: histopathological examination showed lymphocytic infiltration in the lacrymal glands and electroretinogram showed a decrease in the amplitudes of the A + B-wave. By contrast, no drug-related abnormal changes were observed in carteolol-treated dogs. These results were thought to indicate that a tear flow measurement and electroretinogram examination should be used in the evaluation of the safety of beta blocking drugs.