Epidural pethidine in labour. A study of dose requirements.

The degree of pain relief and duration of action were assessed after various doses of epidural pethidine had been given to 12 primigravid mothers in labour. Evidence of sympathetic and motor blockade was sought. Twenty-eight doses were administered and of these 50% gave good pain relief and a further 43% of doses produced some relief. The duration of action was related to dose and varied between 55 min after 25 mg pethidine and 150 min after 100 mg. The blood pressure remained constant and there was no motor blockade. In the postpartum period five mothers expressed full satisfaction and seven were helped by the injection.