[Pethidine or nalbuphine for obstetric analgesia?]

Because of the risk of ventilatory depression, agonistic and partially agonistic/antagonistic opiates are well suited for providing pain relief in obstetrics. We compared two groups of 20 women each with pregnancy on term who received equipotent doses of nalbuphin (0.1 mg/kg) and pethidin (0.8 mg/kg) intramuscularly. We found a significantly longer (6h) and better analgesic effect in the nalbuphin group but also a significantly more pronounced sedation. Other side effects were fewer in this last-named group. There were no differences in the behaviour of the babies between both groups. We consider that because of the "ceiling effect" of ventilatory depression, nalbuphin may allow better analgesia without the risk of ventilatory depression of both mother and newborn.