We previously determined that a single dose of metoclopramide could significantly reduce the patient-controlled analgesia (PCA) morphine requirements of women undergoing prostaglandin-induced termination of pregnancy. In the present study, we evaluated whether repeated doses of metoclopramide would further reduce pain and accelerate expulsion of the fetus. After intraamnionic injection of prostaglandin, patients were randomly allocated to receive either 10 mg of intravenous metoclopramide (n = 17) or saline (n = 15), concurrent with the initiation of PCA. A second, identical dose was administered 4 h later. Data included visual analogue scale scores for pain 45 min after each administration of metoclopramide or saline and visual analogue scale and sedation scores every 2 h for the first 10 h, amount of morphine delivered by PCA pump, time of fetal and placental passage, and hospital discharge. Metoclopramide-treated patients experienced significantly earlier fetal and placental passage (P < 0.05). This was associated with a 66% reduction in PCA morphine received by the time of fetal delivery (P < 0.05). In addition, patients in the metoclopramide group were discharged from the hospital significantly sooner (P < 0.05). This difference included fewer second-day hospital stays (P < 0.05). Visual analogue scale scores measured 45 min after each infusion of the study agent were reduced from baseline in the metoclopramide group only (P < 0.05). No significant intergroup differences were noted with respect to pain or interval morphine usage. We conclude that repeated doses of metoclopramide significantly reduce the duration of induced labor and therefore the total PCA morphine requirements. This effected an earlier hospital discharge for patients undergoing prostaglandin-induced labor. The analgesic potentiating effect of metoclopramide is demonstrable within 45 min of administration.
Address correspondence to Dr. Rosenblatt, Yale University School of Medicine, Department of Anesthesiology, 333 Cedar Street, New Haven, CT 06510.
© 1992 International Anesthesia Research Society