A double blinded randomised placebo‐controlled study of intramuscular pethidine for pain relief in the first stage of labour

Abstract

Objective It has recently been suggested that systemic pethidine is ineffective in relieving labour pain. This study aims to evaluate the analgesic efficacy of pethidine in labour. Design This is a double blinded randomised placebo-controlled study.Setting Labour suite, Prince of Wales Hospital, Hong Kong.Population Fifty normal Chinese pregnant women in early labour.Methods We planned to randomise 112 women in early labour to receive either intramuscular pethidine 100 mg or normal saline when they requested analgesia. An interim analysis was performed at sample size 50. Main outcome measures The primary outcome assessed was the visual analogue scale (VAS) pain score after 30 minutes. Results The study was terminated after recruitment of the first 50 women when planned interim analysis showed a significantly greater reduction of VAS pain score in the pethidine group (P ¼ 0.009). The median difference in VAS pain score between the two groups at 30 minutes was À17 [95% CI À30 to À4]. Mean time to first subsequent request for analgesia was greater in the pethidine group (232 minutes, 95% CI 135 to 329 minutes) compared with the control group (75 minutes, 95% CI 54 to 95 minutes). Eight women (32%) in the pethidine group needed no further analgesia vs one woman (4%) in the control group (P ¼ 0.011). Women in the pethidine group gave greater scores for sedation and satisfaction. Neonatal outcome was similar. Conclusions Systemic pethidine was more effective at relieving labour pain than placebo. Its analgesic effect, however, was modest.

Intravenous patient-controlled analgesia for labour: a survey of UK practice

“…5,6 However, a recent placebo-controlled trial suggests that pethidine does have analgesic effects during labour. 7 Intramuscular diamorphine has been shown to provide better analgesia with fewer side effects than intramuscular pethidine. 8 Although the Royal College of Anaesthetists advocates the preparation of guidelines for management of inadequate regional block or for women receiving thromboprophylaxis, 9 only a third of units have guidelines for pain relief when regional techniques fail or are contraindicated.…”

Prescribing intramuscular opioids for labour analgesia in consultant-led maternity units: a survey of UK practice

“…19,25 The maternal side effects of intramuscular opioids in labour are well known and include sedation, delay in gastric emptying, nausea and vomiting, amnesia and dysphoria which have been reported in at least 25% receiving pethidine in labour. 4,24,[26][27][28][29] Nausea and vomiting may require prophylactic or therapeutic antiemetic therapy. Prochlorperazine was the antiemetic most commonly prescribed.…”

The analgesic efficacy of remifentanil for labour. Systematic review of the recent literature

“…The most commonly used opioid in the past was pethidine, despite the well-described side effects of its metabolite, norpethidine, for both mother and newborn [2][3][4][5][6][7] . Another currently used opioid is nalbuphine but this only reduces the pain slightly [8][9][10][11] . Remifentanil is a synthetic 4-anilide-piperidine, sidechain linked by an ester bond, which is responsible for its rapid inactivation by non-specific hydrolysis of plasma and tissue esterases 12 .…”