Suxamethonium Verapamil

This is a calcium-channel antagonist, which can produce potentiation of suxamethonium and non-depolarizing neuromuscular blockers at doses within the therapeutic range. Verapamil also exacerbates the increase in serum potassium levels after the administration of suxamethonium. To date, there are no established data about such interactions between other calcium-channel blockers and... 

A comparative study in 21 patients taking calcium-channel blockers long term (diitiazem, nifedipine, verapamil) and 15 other patients not taking calcium-channel blockers found that, although suxamethonium (succinylcholine) caused a modest average peak rise of 0.5 mmol/L in plasma potassium levels, there were no differences between the two groups. See also (a) above. 

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