Suxamethonium Droperidol

An isolated report describes prolonged apnoea in a patient given promazine while recovering from neuromuscular blockade with suxamethonium (succinylcholine). Recovery from the neuromuscular blocking effects of suxamethonium is prolonged by fenta-nyl/droperidoL... 

The observation that patients who had received Innovar (fentanyl/droperidol) before anaesthesia appeared to have prolonged suxamethonium effects, seen as apnoea, prompted further study of this possible interaction. An average delay in recovery from neuromuscular blockade of 36% to 80% was seen in two studies. Another study showed that the droperidol component of Innovar was probably responsible for this interaction. 

Not imderstood. It has been suggested that promazine and droperidol depress plasma cholinesterase levels, which would reduce the metabolism of the suxamethonium and thereby prolong recovery. It has also been suggested that droperidol might act as a membrane stabiliser at neuromuscular jimctions. ... 

Delayed recovery should be anticipated in patients given suxamethonium if droperidol is used. This is an established interaction. 

---