The reversal effect of low dose aminophylline on thiopental-induced sedation.

Fifty-two ASA (American Society of Anesthesiologists) class I-II female patients, from 22 to 66 years of age, undergoing D & C (dilatation and curettage) procedure, were randomly divided into 2 groups in a double-blind and placebo-controlled design to investigate whether aminophylline could reverse the sedative effect of thiopental. Patients of both groups were anesthetized with fentanyl (2 micrograms/kg, i.v.) and thiopental (4 mg/kg, i.v. and 1 mg/kg, i.v. repeated if necessary). Postoperatively, they were intravenously given aminophylline (2 mg/kg) or normal saline in an equal volume solution over 5 minutes. The results showed that patients in the aminophylline group were more sedated (p < 0.05) than in the saline group 5 minutes after reversal, but were less sedated (p < 0.05) at minute 20. No significant differences between groups were found at other times. The total time spent in the postanesthetic unit was shorter in the aminophylline group (92 +/- 27 min.) than in the normal saline group (109 +/- 30 min.) (p < 0.05). The serum theophylline levels in some cases in the aminophylline group ranged between 3.2 and 4.9 micrograms/ml (4.3 +/- 0.7 micrograms/ml, n = 10). No apparent side effects, including tachyarrhythmias, were noted. We conclude that low dose aminophylline (2 mg/kg, i.v.) can partially reverse thiopental-induced sedation with safety in the early phase of recovery and it can reduce the total time spent in the postanesthetic unit.