Response to suxamethonium in a myasthenic patient during remission.

A cumulative dose followed by an infusion was used to determine the dose response to suxamethonium in a patient with diagnosed myasthenia gravis who was in true remission (asymptomatic while receiving no therapy). The ED50 and ED90 values for suxamethonium were 0.08 mg/kg and 0.20 mg/kg, and an infusion rate of 3.2 mg/kg/hour was required to maintain a 90-95% depression of the single twitch response as monitored by integrated electromyography. These values are within the range for normal patients, and we conclude that myasthenic patients during a true remission may not demonstrate resistance to suxamethonium.