Sufentanil–ropivacaine eases labour pain better than nalbuphine–ropivacaine

The kappa-opioid receptor agonist nalbuphine appears to provide subpar analgesic effects compared with the mu receptor agonist sufentanil when added to ropivacaine in the management of labour pain in women, a study has shown.

A total of 180 women who were about to give birth and requesting pain relief during labour were randomized to receive nalbuphine or sufentanil. Five minutes after the initial dose, the women were administered 10 mL of 0.1% ropivacaine plus either 0.3 mg/mL nalbuphine solution or 0.3 μg/mL sufentanil.

The primary outcome of the duration of analgesia (the time to the first requirement for additional medication) was significantly shorter on nalbuphine than on sufentanil (p=0.040).

Furthermore, the ropivacaine dose per hour in the nalbuphine group was significantly greater than in the sufentanil group (mean, 9.3 vs 8.4 mg; p=0.024).

There were no serious adverse events directly associated with the analgesics seen either in the mother or in the foetus.

During epidural labour analgesia, the addition of a small dose of opioids has the potential to enhance the local analgesic effect, reduce the dose of local anaesthetic required, and minimize motor blockade. Previous reports cite that kappa-opioid receptor agonists are more effective than mu receptor agonist for the treatment of visceral pain. However, the present study suggests that sufentanil may be preferable to nalbuphine for women requesting pain relief during labour.