Myalgia and biochemical changes following suxamethonium after induction of anaesthesia with thiopentone or propofol.

The incidence and severity of muscle pains and changes in creatine kinase were assessed following administration of 1 mg.kg-1 suxamethonium either immediately or 2 min after induction of anaesthesia with propofol or thiopentone in patients undergoing elective dental and ophthalmic surgery. The incidence of muscle pains was 35 and 60% respectively in the groups given suxamethonium immediately and 2 min after propofol, and 35 and 55% when given immediately and 2 min after thiopentone, with no statistically significant differences among the groups. Creatine kinase levels increased in all the groups after operation with the least average increase in the group receiving suxamethonium immediately after propofol and the highest increase in the group receiving suxamethonium 2 min after thiopentone. There was no correlation between the incidence and severity of fasciculations, muscle pains and changes in creatine kinase within or between the groups. It is concluded that neither the induction agent nor the time between the induction agent and suxamethonium administration has any significant influence on the incidence of muscle pains or creatine kinase elevation following suxamethonium.