Effects of verapamil, diltiazem, propanolol and quinidine on RO 13-6438-induced cardiac dysrhythmia in guinea pigs

The effect of Verapamil, Diltiazem, Propranolol and Quinidine on Ro 13-6438-induced cardiac dysrhythmia in urethane-anaesthetized guinea pigs was studied. During this study, the tested drugs were given in advance to visualize if they can protect the animal from a subsequent dose of Ro 13-6438. Intravenous injection of Ro 13-6438 in a dose level of 50 mg/kg was able to produce persistent period of ventricular tachycardia ended with the development of ventricular fibrillation. Verapamil, Diltiazem, in a dose level of 5 mg/kg and Propranolol, in a dose level of 2.5 mg/kg, were found to protect animals against dysrhythmia induced by Ro 13-6438, whereas Quinidine, in a dose level of 5 mg/kg, was found to be ineffective. A possible role of electrolytes in the genesis of Ro 13-6438-induced cardiac dysrhythmia was discussed