Introduction: Succinylcholine is a depolarizing muscle relaxant, which has been used extensively in anesthesia to produce muscle relaxation. The present study was done with the aim of comparing Fasciculation and postoperative myalgia after injection of two different doses of Succinylcholine (1.5 mg/kg and 3 mg/kg).

Materials and Methods: In this study which has been conducted in the form of Randomized double blind study in Tehran Shariati Hospital in the year 2000, 50 male patients in two groups (25 in each) with ASA I&II, age between 18 to 65, were candidate for an elective surgical repair of inguinal hernia received a standard anesthetic technique, including one of the two doses of Succinylcholine.

Results: After collecting data it has been considered that the average difference of two respective groups is meaningful in terms of fasciculation (P<0.05), but not in terms of myalgia (P>0.05).

Conclusion: we came to the conclusion that, firstly, the percentage of myalgia after the injection of succinylcholine is totally low and with the increase of the dose of medication from 1.5 mg/kg to 3 mg/kg the very percentage does not change considerably. Secondly, regarding fasciculation the increase of the dose of medication from 1.5 mg/kg to 3 mg/kg causes the decrease of the average limit of fasciculation. This decrease is very obvious in server fasciculation. As a matter of fact no relationship was found between decrease in fasciculation and change in myalgia.