Pain Relief and Plasma Concentrations from Epidural and Intramuscular Morphine in Post-Cesarean Patients

Analgesic efficacy and adverse effects of epidural morphine compared to parenteral opioids after elective caesarean section: A systematic review

“…The EM dose varied between 1 and 8 mg. Two studies were not blind (Eisenach et al, 1988; Harrison et al, 1988). Four studies compared EM to placebo (Carmichael et al, 1982; Celleno et al, 1991; Coombs et al, 1982; Palmer et al, 2000) and six trials compared EM to parenteral opioids (Cohen and Woods, 1983; Eisenach et al, 1988; Harrison et al, 1988; Rapp‐Zingraff et al, 1997; Rosen et al, 1983; Youngstrom et al, 1982). In the studies comparing EM to placebo, postoperative analgesia for parturients receiving placebo consisted of parenteral opioids given only on demand.…”

“…In the studies comparing EM to placebo, postoperative analgesia for parturients receiving placebo consisted of parenteral opioids given only on demand. In the studies comparing EM to parenteral opioids, parturients in the parenteral opioid group systematically received parenteral morphine by intravenous patient controlled analgesia (PCA) with morphine (Rapp‐Zingraff et al, 1997), intravenous titrated morphine (Cohen and Woods, 1983), or intramuscular morphine (Rosen et al, 1983; Youngstrom et al, 1982). Two studies included two parenteral opioid groups (Eisenach et al, 1988; Harrison et al, 1988), one intravenous PCA morphine group and one intramuscular morphine group, compared one to each other and to an EM group.…”

“…Epidural anaesthesia was performed for surgery in all the studies except one (Rapp‐Zingraff et al, 1997), where a combined spinal epidural technique was performed. The local anaesthetics used were bupivacaine 0.5% (Eisenach et al, 1988; Rapp‐Zingraff et al, 1997) or 0.75% (Cohen and Woods, 1983; Coombs et al, 1982; Rosen et al, 1983), or lidocaine 2% with epinephrine (Carmichael et al, 1982; Celleno et al, 1991; Harrison et al, 1988; Palmer et al, 2000; Rosen et al, 1983) or chloroprocaine (Youngstrom et al, 1982). EM injection was performed before surgery, concomitantly with the local anaesthetic injection (Celleno et al, 1991; Coombs et al, 1982), 10–20 min after the last epidural injection of local anaesthetic for surgery (Youngstrom et al, 1982), at the time of umbilical cord clamping (Harrison et al, 1988), just after delivery (Eisenach et al, 1988; Palmer et al, 2000), at the time of skin closure (Carmichael et al, 1982), as the patients were admitted to the recovery room (Rapp‐Zingraff et al, 1997), at the first patient's complain of pain (Rosen et al, 1983), or 1 h after the end of surgery (Cohen and Woods, 1983).…”

The Rational Use of Intrathecal and Extradural Opioids

“…Available evidence confirms that analgesia results from a regional rather than a systemic effect, although there may be some initial contribution from the latter. Pharmacokinetic studies have found no relationship between quality of analgesia and plasma concentrations of the drug, which have been well below reported "analgesic" concentrations [134,178,195,208]. Indeed, excellent analgesia may be present with no morphine detectable in the plasma.…”

Metastatic pain in the parturient: treatment with patient‐controlled epidural sufentanil

“…The aim is to provide "selective" analgesia at spinal cord level while minimising the systemic effects of narcotics. Epidural opioids can provide adequate analgesia with lower systemic narcotic levels (5,6)' and have been used to provide analgesia for cancer pain resistant to more conventional regimes (2). Although we had no information on the systemic uptake of epidural sufentanil, there is evidence that epidural fentanyl, another lipophilic opioid, provides good analgesia at lower plasma levels than when it is given systemically (5), although this is controversial (7).…”