Intravenous morphine and oxycodone for pain after abdominal surgery

Abstract

Intravenous morphine and oxycodone were given double blind in doses of 0.05 mg/kg after major abdominal surgery to 39 patients. The dosing interval was 5 min, until the patient did not want any further analgesics. Less oxycodone was needed than morphine, both to achieve the "first state of pain relief" (13.2 mg vs. 24.9 mg) and during the whole 2-h study period (21.8 mg vs. 34.2 mg). The "first state of pain relief" was achieved faster (28 min vs. 46 min) and lasted longer (39 min vs. 27 min) with oxycodone than morphine. Morphine caused more sedation and a greater decrease in the mean arterial blood pressure than oxycodone. In other respects the two opioids were comparable.

The pharmacokinetics of oxycodone after intravenous injection in adults.

“…The study was carried out at about 13 h after surgery, as general anaesthesia may interfere with the pharmacokinetics of many drugs. The present results are in agreement with our previous findings demonstrating that the duration of the analgesic effect of intravenous oxycodone after abdominal surgery is longer than that of intravenous morphine (Kalso et al, 1991). It has been suggested that some of the analgesic effect of oxycodone might be due to its active metabolites (Kalso et al, 1990).…”

“…Oxycodone (14-hydroxy-7,8-dihydrocodeinone) is a semisynthetic opioid, with effects similar to those of morphine (Kalso et al, 1990(Kalso et al, , 1991Saarialho-Kere et al, 1989). Noroxycodone (Weinstein & Gaylord, 1979) and oxymorphone (Baselt & Stewart, 1978) are thought to be the main metabolites of oxycodone in man.…”

Morphine or Oxycodone in Cancer Pain?

“…Clinical studies have shown that oxycodone provides ef cient pain relief in acute postoperative pain (5) and in chronic pain (6). Oxymorphone, an active metabolite of oxycodone, is formed in the liver in an O-demethylation reaction, mediated by the enzyme CYP2D6 (7).…”

Comparison of oxycodone and fentanyl for postoperative patient-controlled analgesia after orthopedic surgery

“…Numerous studies have suggested that IV oxycodone is an effective treatment for acute postoperative pain [16,17]. Furthermore, determination of the proper dosage regimen of oxycodone is important for effective pain control.…”

“…Oxycodone is an effective analgesic agent for visceral pain and somatic pain, but studies to date have shown that it is more effective for visceral pain [7][8][9]27]. Likewise, pain after abdominal surgery is controlled by similar or smaller amounts of oxycodone compared with the equipotent ratio of morphine or fentanyl [16][17][18][19][20][21][22]. Therefore, in somatic pain such as pain after orthopedic surgery, the amount of oxycodone should be higher than the dose used for visceral pain.…”