Postoperative myalgia after succinylcholine: no evidence for an inflammatory origin

A common side effect associated with succinylcholine is postoperative myalgia. The pathogenesis of this myalgia is still unclear; inflammation has been suggested but without convincing evidence. We designed the present study to investigate whether an inflammatory reaction contributes to this myalgia. The incidence and severity of succinylcholine-associated myalgia was determined in 64 patients pretreated with saline or dexamethasone before succinylcholine (n = 32 for each). Incidence and severity of myalgia did not differ significantly between the two groups: 15 patients in the dexamethasone group complained of myalgia compared with 18 patients in the saline group, and severe myalgia was reported by five patients and three patients, respectively (not significant). At 48 h after surgery, 12 patients in both groups still suffered from myalgia (not significant). In addition, interleukin-6 (IL-6) as an early marker of inflammation was assessed in a subgroup of 10 patients pretreated with saline. We found an increase of IL-6 for only three patients, but only one patient reported myalgia; no relationship between myalgia and the increase of IL-6 was found. In conclusion, there is no evidence for an inflammatory origin of succinylcholine-associated myalgia.

Administration of dexamethasone before succinylcholine was not effective in decreasing the incidence or the severity of succinylcholine-induced postoperative myalgia. Furthermore, there was no significant relationship between postoperative myalgia and time course of interleukin-6 concentrations, a marker of inflammation. Pretreatment with dexamethasone is not justified to prevent postoperative myalgia after succinylcholine.