Intrathecal bupivacaine reduces pruritus and prolongs duration of fentanyl analgesia during labor: a prospective, randomized controlled trial.

Abstract

Pruritus is a frequent complication (40%-100%) of intrathecal (IT) fentanyl 25 microg (F) for labor analgesia. The addition of IT bupivacaine 2.5 mg (B) to F has been reported in a nonrandomized series to have a 17.3% incidence of pruritus. This study prospectively evaluated the incidence and distribution of pruritus in laboring parturients receiving IT F + B. Sixty-five laboring parturients were randomly assigned to receive IT F, B, or F + B as part of a combined spinal-epidural technique. Visual analog scores, sensory level, motor strength, and pruritus were recorded before injection and at intervals thereafter. When present, the distribution of pruritus was evaluated. The duration of analgesia was determined as the time from IT drug administration until the patient requested supplemental analgesia. The median duration of analgesia in the F, B, and F + B groups was 62.5, 55.0, and 94.5 min, respectively. Compared with F alone, the combination of F + B led to a decreased frequency of pruritus (36.4% vs 95%). The incidence of facial pruritus (25%) was same in the F + B and F groups; however, the occurrence of pruritus distributed over the rest of the body was significantly more frequent in the F compared with the F + B group. The combination of F + B prolongs the duration of labor analgesia compared with IT F or B alone. F + B also leads to a decreased incidence of pruritus, except in the facial region. When administered intrathecally with fentanyl 25 microg in laboring parturients, bupivacaine 2.5 mg attenuates the frequency of pruritus on all parts of the body except the face. This combination also results in a rapid onset and prolonged duration of labor analgesia compared with either drug alone.