Analgesic interaction between butorphanol and sufentanil

Abstract

Objective To evaluate the analgesic interaction between butorphanol and sufentanil. Methods Ninety patients, aged 18-64 yr, with body mass index 50% within 15 min after administration.The median effective dose(ED50)and 95% confidence interval(CI)of butorphanol and sufentanil were calculated by probit analysis.Isobolographic analysis was used to analyze the analgesic interaction between butorphanol and sufentanil.When the equivalent dose of two drugs was very different from that selected in group BS1 on the basis of the actually calculated ED50 in B and S groups, the combination of butorphanol and sufentanil in group BS2(n=30)was set at the ratio of 1∶1 based on the actual equivalent dose: the initial dose was butorphanol 0.4 mg plus sufentanil 1.8 μg with 0.1 mg and 0.45 μg increment/decrement for butorphanol and sufentanil, respectively. Results The ED50 of butorphanol was 0.80 mg(95% CI 0.74-0.87 mg), and the ED50 of sufentanil was 3.68 μg(95% CI 3.07-4.41 μg). The ED50 of butorphanol and sufentanil was 0.28 mg(95% CI 0.25-0.32 mg)and 2.82 μg(95% CI 2.52-3.16 μg), respectively, in group BS1.The ED50 of butorphanol and sufentanil was 0.38 mg(95% CI 0.33-0.43 mg)and 1.7 μg(95% CI 1.5-1.9 μg), respectively, in group BS2.The isobolographic analysis showed that the combination of butorphanol and sufentanil at 2∶1 or 1∶1 produced an additive analgesic effect. Conclusion The analgesic effect of butorphanol and sufentanil is additive when combined at the ratio of 2∶1 or 1∶1 based on the equivalent dose. Key words: Butorphanol; Sufentanil; Drug interactions