Comparison of Four Narcotic Analgesics for Extradural Analgesia

Abstract

The effectiveness of extradural injections of morphine sulphate 6 mg, methadone 6 mg, pethidine 60 mg and fentanyl 60 micrograms in relieving pain after operation were compared in 24 patients. The average duration of pain relief following morphine was 12.3 h; methadone 8.7 h, pethidine 6.6 h and fentanyl 5.7 h. There was no significant difference in the efficacy of the four drugs. There were no effects of clinical importance on heart rate, respiratory frequency or arterial pressure, but arterial systolic pressure decreased after morphine and pethidine. Pethidine also caused a statistically significant reduction in diastolic pressure.

Side‐effects of epidural infusions of opioid bupivacaine mixtures

“…It is anticipated that if no patients had been electively catheterised this difference would have been even greater. Previous studies have also shown a high incidence of catheterisation with epidural morphine ranging from 10% (retrospective) to 100% [2,3,12,15,18,20,30,31,52,53] and again this appears to be dose dependent. A retrospective study of 2000 women receiving epidural pethidine failed to demonstrate any evidence of urinary retention [37].…”

“…Most studies have given an opioid bolus and assessed the analgesic effect and the duration of action [3,4,7,9,14,[16][17][18][19][20][21][22][23]. From these data we calculated approximately equipotent 24-h dosages for each drug.…”

“…Previous studies comparing epidural opioids have included patients having a variety of surgical procedures and anaesthetic techniques [1][2][3]. The patients often received opioids by more than one route in the perioperative period and observations on side-effects were, in many cases, retrospective [1,[3][4][5][6][7].…”

“…The patients often received opioids by more than one route in the perioperative period and observations on side-effects were, in many cases, retrospective [1,[3][4][5][6][7].…”

Extradural anesthesia with lidocaine combined with fentanyl or methadone to ovariohisterectomy in dogs

“…The mechanism of respiratory depression after epidural morphine seems to be related to morphine's low lipid solubility. In comparison with hydrophilic drugs, the rapid uptake of extradural lipophilic compounds reduces their capacity to cause late respiratory depression 20 .…”