The effect of quinidine and procainamide on the neuromuscular blocking action of suxamethonium.

Previous workers have shown that under certain clinical and experimental conditions, quinidine potentiates the neuromuscular blocking action of suxamethonium. This effect of quinidine has been demonstrated experimentally in a nerve-musde preparation in vivo while another antifibrillatory drug, procainamide, has also been shown to potentiate suxamethonium. Possible explanations of these drug interactions are discussed. Since quinidine is known to cause respiratory paralysis in man when administered intravenously during the recovery phase from suxamethonium block, it is suggested that procainamide may produce similar effects in this situation.