Epidural butorphanol-bupivacaine for analgesia during labor and delivery.

A double-blind, randomized, dose-response study of a combination of 0.25% bupivacaine combined with 0, 1, 2, or 3 mg of butorphanol was studied in 40 laboring parturients. The optimal dose of butorphanol combined with 8.5 to 10 ml 0.25% bupivacaine was 2 mg; with 2 mg, the duration of analgesia was significantly greater and the time to onset of analgesia significantly shorter than when no butorphanol was added, and the amount of bupivacaine could be reduced 50%. Adverse fetal effects were not observed except that of a low amplitude sinusoidal fetal heart rate pattern with doses of 3 mg butorphanol. All neonatal observations were normal. It is concluded that epidural butorphanol can be a useful and safe adjunct to bupivacaine used for epidural analgesia during labor.