Neuromuscular Blockade of Mivacurium Following the Duration of Isepamicin Intramuscular Injection in Rabbits

chung, Chang Woo; Yoo, Hee Koo; Kim, Kyo Sang; Min, Jin Hye; Kim, Kyung Hyun

Abstract

BACKGROUND: Isepamicin, a new aminoglycoside antibiotic, was usually administered to patients for prophylactic use. Mivacurium has a short duration of action. The current study was undertaken to evaluate the neuromuscular blockade of mivacurium following the duration of an intramuscular injection of isepamicin 20 mg/kg/d in rabbits.
METHODS
In the first study, the dose-response relations of mivacurium were studied in forty rabbits during thiopental anesthesia. Rabbits were randomly assigned to four groups; group 1: normal saline 2 ml/d IM for 7 days; group 2: isepamicin 20 mg/kg/d IM for 1 day; group 3: isepamicin 20 mg/kg/d IM for 3 days; group 4: isepamicin 20 mg/kg/d IM for 7 days. They received mivacurium 10, 20 and 30ng/kg in groups 1, 2 and 3; mivacurium 20, 30 and 40ng/kg in group 4, respectively. In the second study, time courses of action of mivacurium 0.18 mg/kg in forty rabbits were evaluated in each group.
RESULTS
The calculated ED50 for mivacurium in groups 1, 2, 3 and 4 were 19.2 +/- 3.1ng/kg, 15.4 +/- 3.7ng/kg, 20.1 +/- 3.5ng/kg and 31.2 +/- 4.4ng/kg, respectively and corresponding ED95 was 29.9 +/- 3.7ng/kg, 22.1 +/- 4.5ng/kg, 30.1 +/- 5.9ng/kg and 43.4 +/- 5.1ng/kg, respectively. There were significant differences between group 4 and the others (P < 0.05). In the second study, the times after mivacurium 0.18 mg/kg until 95% twitch recovery in groups 1, 2, 3 and 4 were 35.1 +/- 5.1 min, 42.2 +/- 6.2 min, 32.8 +/- 4.9 min and 24.9 +/- 3.6 min, respectively. There were significant differences between group 2 and others, and between group 4 and group 1 or 3, respectively (P < 0.05).
CONCLUSIONS
Mivacurium when used as a bolus isepamicin therapy, has both an increased potency and a longer duration of action, but when used during concurrent isepamicin therapy, has both a decreased potency and a shorter duration of action.