Diamorphine, the obstetric analgesic: a neurobehavioural and pharmacokinetic study in the neonate

Summary

Scanlon scores were used to determine the neurobehavioural effects of maternally administered intramuscular diamorphine (10 mg) on 26 neonates in the first 5 days of life. Half received intramuscular naloxone at birth and these two groups were compared with 13 babies not exposed to analgesic drugs in utero or to antagonists. No significant differences were observed between the three groups and no long term differences emerged by 12 months. Maternal analgesic efficacy of diamorphine in labour was satisfactory. The mean cord: maternal plasma ratio of ‘morphine equivalents' at delivery was 1·59·84 (s.d.), determined by radioimmunoassay Diamorphine and its metabolites underwent rapid elimination from the plasma, unlike the slower elimination of pethidine from neonatal plasma. It is concluded that diamorphine might warrant more widespread use as an obstetric analgesic.