Augmentation of Bupivacaine Analgesia in Labor by Epidural Morphine

Controlled Trial of Extradural Bupivacaine With Fentanyl, Morphine or Placebo for Pain Relief in Labour

“…In pregnant women, extradural morphine alone, in a dose of 5 mg or less, is ineffective in providing satisfactory pain relief throughout labour [1,3,[5][6][7][8][9], probably because the extradural vascular congestion of pregnancy enhances vascular absorption of morphine [18][19][20][21][22][23][24]. Several investigators have reported that extradural bupivacaine improves the quality of analgesia when administered after [9] or simultaneously with [12] extradural morphine during the first stage of labour. However, in our double-blind study we could not demonstrate any improvement in analgesia by combining morphine with bupivacaine.…”

“…The use of extradural opioids for pain relief in labour has been shown to be inefficient and hazardous [1][2][3][4][5][6][7][8][9]. It has been demonstrated, however, that the combination of an opioid and a local anaesthetic may improve both the onset and the duration of analgesia produced by the latter, and provide better quality of analgesia [10][11][12][13].…”

“…Niv and co-workers concluded that the concomitant use of extradural morphine 2 mg augmented the analgesic effect of 0.25% bupivacaine [12], but Cohen and colleagues found that the addition of extradural fentanyl 50 or 100 ug to 0.25 % bupivacaine 9 ml did not result in significant improvement in analgesia compared with the local anaesthetic alone [14]. The majority of clinical trials have been limited to small numbers of parturients, and none has compared fentanyl with morphine in combination with extradural bupivacaine.…”

The addition of epidural morphine to ropivacaine improves epidural analgesia after lower abdominal surgery

“…While the epidural infusion of 0.2% ropivacaine at the rate of 6 mL·hr -1 produces less motor block, it is less effective for postoperative analgesia than at the rate of 10 to 14 mL·hr -1 . 11 We cannot explain the reason for the observed increase in the incidence of motor block in patients receiving the combination. However, patients receiving the combination showed a weak but significant motor block two hours after the start of infusion, while patients receiving only one of the drugs did not.…”