A comparison of the combination of atropine and glycopyrrolate with atropine alone for the reversal of muscle relaxant.

BACKGROUND: Muscle relaxant is commonly used in general anesthesia to facilitate surgery. When finishing the operation, anesthesiologists reverse the muscle relaxant with anticholinesterase, neostigmine, combined with anticholinergic for prevention of unwanted side effects from neostigmine. The only existed anticholinergic in Thailand is atropine, which has a more rapid onset than neostigmine resulting in initial tachycardia. Lately, we have glycopyrrolate that cause less increase in initial heart rate. Therefore, we would like to study the effect of heart rate of the combination between atropine and glycopyrrolate to counteract the effect of neostigmine.

OBJECTIVE: Evaluate the different increase in heart rate after the reversal of muscle relaxant with neostigmine combined with atropine or glycopyrrolate plus atropine.

MATERIAL AND METHOD: The study was a randomized controlled trial study. Fifty-one, ASA I or II patients undergoing elective gynecological surgery under general anesthesia technique were enrolled in the present study. They were randomly assigned by computer-generated random sequence into two groups, control group and intervention group. Control group received neostigmine 2.5 mg and atropine 1.2 mg, intervention group received neostigmine 2.5 mg, glycopyrrolate 0.2 mg and atropine 0.6 mg for reversal of neuromuscular block after finishing the operation. Both groups received the same anesthetic agents including muscle relaxant. Heart rate was recorded before drugs administration and at 1, 3, 5, and 7 minutes after injection. We also recorded heart rate in the PA CU at 0, 15, 30, 45, and 60 minutes. Secondary outcome was incidence of arrhythmia during the observation in PACU.

RESULTS: There was no difference in age and baseline heart rate between the two groups. There was no different increase in heart rate after administration of reversal agent between control group and intervention group at any time (p-value = 0.496). No incidence of significant arrhythmia in both groups.

CONCLUSION: There is no significant different increase in heart rate in 0.2 mg glycopyrrolate plus 0.6 mg atropine group compared to 1.2 mg atropine alone for antagonizing muscarinic effects of 2.5 mg neostigmine. Therefore, atropine 0.6 mg and glycopyrrolate 0.2 mg is an alternative to antagonize muscarinic effects of neostigmine.