Ventilatory Depression of the Newborn of Women Receiving Pethidine or Pentazocine

Abstract

Forty-two women at term received pethidine 100 mg and 43 received pentazocine 45 mg, both given in a double-blind randomized manner. There was no difference in analgesic effect between the groups, but twelve patients were judged to need more than one injection of pentazocine, compared with seven in the pethidine group. The Apgar scores at 1 and 5 min were significantly less in the pethidine group. Four neonates in the pethidine group and two in the pentazocine group were severely depressed and received naloxone between 5 and 15 min after birth. The remainder of the infants received naloxone 200 microgram i.m. 15 min after birth. From 5 min after birth, end-expiratory carbon dioxide concentrations and from 15 min transcutaneous PO2 were recorded. A significantly smaller end-tidal carbon dioxide concentration was measured when more than one injection of pentazocine had been given. Repeated doses of pethidine, on the other hand, resulted in a greater end-tidal carbon dioxide concentration. Vigorous ventilation was even more pronounced when naloxone was given indicating an analeptic effect when two drugs with antagonistic activity are combined. At no time was transcutaneous PO2 less than 6.1 kPa. We conclude that both pethidine and pentazocine produce adequate pain relief during labour, but more than one injection of pethidine is associated with greater neonatal depression.

Hazards of pentazocine for neonatal analgesia: a single-centre experience over 10 years

“…This has been reported to be a cause of unexplained respiratory problem in neonates who otherwise had smooth anaesthesia and surgery. 4,7,8 In this report, the analgesia provided by pentazocine was satisfactory in only 4.1% of neonates who scored ,6 using the adapted NIPS scale. 9 Many of the neonates would have survived in developed countries but the outcome in this centre was poor because there was no paediatric respiratory support and the neonatal intensive care unit was poorly organised during the study period.…”

“…4,5,10 Of the 49 neonates who received pentazocine during the study period, complications ranging from over-sedation to death were recorded in 47 (95.9%). The 15 (30.6%) deaths were mainly owing to respiratory depression which was compounded by the unavailability of a paediatric ventilator, as observed by others.…”

“…It was most useful in reversing the respiratory depression at the onset, less effective after 12 hours of administration of pentazocine when the depression has had time to establish itself, and not useful after 24 hours. 4,5,7,8 Two neonates received more than one dose of naloxone. The absence of cardiopulmonary anomalies at autopsy which could cause respiratory problems and the response of the majority of neonates to naloxone were pointers to the fact that pentazocine was the main cause of the respiratory depression.…”

“…2 Respiratory depression associated with opioids and other analgesics has been documented in neonates. [3][4][5][6][7][8] In many health institutions in sub-Saharan Africa, the selection of safe and effective analgesics for neonates undergoing surgery is a major challenge. This is because of the unavailability of paediatric ventilators in many centres.…”

“…The risk of using an analgesic with proven respiratory depression in neonates in such centres might outweigh their benefits. 4 Reports from developed countries where there are adequate ventilatory facilities mention respiratory depression with the use of pentazocine in neonates but have not recorded associated life-threatening morbidity or mortality. 4,5,7,8 Little attention has been paid to the hazards associated with the use of pentazocine in neonates in developing countries where facilities for respiratory support are scarce.…”