Single-dose dextropropoxyphene in post-operative pain: a quantitative systematic review

Objective: To determine the analgesic efficacy and adverse effects of single-dose oral dextropropoxyphene alone and in combination with paracetamol for moderate to severe post-operative pain. Methods: Published reports were identified from a variety of electronic databases including MEDLINE, Biological Abstracts, EMBASE, the Cochrane Library and the Oxford Pain Relief Database. Additional studies were identified from the reference lists of retrieved reports. Summed pain intensity and pain relief data were extracted and converted into dichotomous information to yield the number of patients with at least 50% pain relief. This was used to calculate the relative benefit and number-needed-to-treat for one patient to achieve at least 50% pain relief. Six reports (440 patients) compared dextropropoxyphene with placebo and five (963 patients) compared dextropropoxyphene plus paracetamol 650 mg with placebo. Results: For a single dose of dextropropoxyphene 65 mg in post-operative pain the number-needed-to-treat for at least 50% pain relief was 7.7 (95% confidence interval 4.6 to 22) when compared with placebo over 4-6 h. For the equivalent dose of dextropropoxyphene in combination with paracetamol 650 mg the number-needed-to-treat was 4.4 (3.5 to 5.6) when compared with placebo. Pooled data showed increased incidence of central nervous system adverse effects for dextropropoxyphene plus paracetamol when compared with placebo. A rank order of single-dose analgesic effectiveness in post-operative pain of moderate to severe intensity obtained from similar systematic reviews is presented. Conclusion: Dextropropoxyphene 65 mg plus paracetamol 650 mg has a similar analgesic efficacy to that of tramadol 100 mg but with a lower incidence of adverse effects. Ibuprofen 400 mg has a lower (better) number-needed-to-treat than both dextropropoxyphene 65 mg plus paracetamol 650 mg and tramadol 100 mg.