Myalgia and biochemical changes following intermittent suxamethonium administration

One hundred gynaecological patients for laparoscopy divided into five groups were studied to determine the effects of a number of pretreatments on serum myoglobin, creatinine kinase and myalgia following intermittent suxamethonium administration. One group acted as controls, while the other groups were given intravenous pretreatments of alcuronium 2 mg, midazolam 0.15 mg/kg, lignocaine 1.5 mg/kg and suxamethonium 7 mg. Serum myoglobin was determined by radio-immunoassay. The mean increases in the control group were 167 micrograms/litre myoglobin at 20 minutes and 196 IU creatinine kinase at 24 hours; 13 out of 20 patients responded with a marked increase of serum myoglobin at 20 minutes and of creatinine kinase at 24 hours. Only alcuronium pretreatment prevented myoglobin increase at 20 minutes, abolished creatinine kinase increase at 24 hours and reduced 24-hour myalgia. The other pretreatments slightly reduced myoglobin increase at 20 minutes and 24-hour creatinine kinase but did not reduce myalgia. Only one patient in the whole study had markedly elevated serum myoglobin at 24 hours. We conclude that only non-depolarising relaxant pretreatment is effective in the reduction of some of the adverse effects of suxamethonium administration.