Single dose oxycodone and oxycodone plus paracetamol (acetominophen) for acute postoperative pain

Oxycodone is a strong opioid agonist which is useful for the management of severe pain. It is becoming increasingly important to assess the relative efficacy and harm caused by different treatments. This can be determined when an analgesic is compared with control under similar clinical circumstances.

To quantitatively assess the analgesic efficacy and adverse effects of single-dose oxycodone and oxycodone plus paracetamol in randomised trials in acute postoperative pain.

Published reports were identified from Medline, Biological Abstracts, Embase, the Cochrane Library and the Oxford Pain Relief Database. Additional studies were identified from the reference lists of retrieved reports.

The inclusion criteria were: full journal publication, clinical trial, random allocation of adult patients to treatment groups, double blind design, moderate to severe baseline pain, postoperative administration of study drugs, treatment arms which included oxycodone or oxycodone plus paracetamol and placebo (or active control for which comparable efficacy data exist), and oral, intramuscular or intravenous administration of study drugs.

Summed pain intensity and pain relief data over 4-6 hours were extracted and converted into dichotomous information yielding the number of patients obtaining at least 50% pain relief. Estimates of relative benefit and number-needed-to-treat were calculated. Single-dose adverse effect data were collected.

Seventy-seven reports were identified. Seven reports met the inclusion criteria; all assessed oral oxycodone. For efficacy, a significant benefit of active drug over placebo was shown for all doses of oxycodone and oxycodone plus paracetamol, except oxycodone 5 mg. For adverse effects, the number of patients reporting adverse effects was extracted for each dose of active drug versus placebo. When these data were pooled for the individual doses significantly more adverse effects with active drug than with placebo were shown for all doses, except oxycodone 5 mg and its combination with paracetamol 325 mg. This was also shown for drowsiness/somnolence. Significantly more nausea, vomiting and dizziness/lightheadedness were reported with oxycodone 10 mg plus paracetamol (650 mg and 1000 mg) than with placebo.

Single-dose oral oxycodone, with or without paracetamol, appears to be of comparable efficacy to intramuscular morphine and non-steroidal anti-inflammatory drugs. Central nervous system adverse effects were common.