Suxamethonium infusion rate and observed fasciculations. A dose-response study.

Suxamethonium chloride (Sch) was administered i.v. to 36 adult males at six rates: 0.25 mg s-1 to 20 mg s-1. The infusion was discontinued either when there was no muscular response to tetanic stimulation of the ulnar nerve or when Sch 120 mg was exceeded. Six additional patients received a 30-mg i.v. bolus dose. Fasciculations in six areas of the body were scored from 0 to 3 and summated as a total fasciculation score. The times to first fasciculation, twitch suppression and tetanus suppression were inversely related to the infusion rates. Fasciculations in the six areas and the total fasciculation score were related directly to the rate of infusion. Total fasciculation scores in the 30-mg bolus group and the 5-mg s-1 and 20-mg s-1 infusion groups were not significantly different.