Postoperative pain relief with pentazocine and acetaminophen: comparison with other analgesic combinations and placebo.

A single-blind, parallel-group study was carried out to evaluate the efficacy and safety of an analgesic combining 650 mg of acetaminophen and 25 mg of pentazocine in 129 patients with moderate postoperative pain. Comparisons were made with a combination containing acetaminophen (300 mg) and codeine (30 mg), a combination containing acetaminophen (650 mg) and propoxyphene napsylate (100 mg), and a placebo. A nurse observer queried patients at regular intervals over a six-hour period concerning the intensity of pain and the degree of pain relief. The scores obtained were used in the calculation of standard measures of analgesic efficacy. Acetaminophen/pentazocine proved to be significantly superior to placebo and equivalent to the other active analgesic combinations. No side effects were reported with acetaminophen/pentazocine, acetaminophen/propoxyphene napsylate, or placebo. One mild side effect was questionably associated with acetaminophen/codeine. This study demonstrates that the combination of acetaminophen and pentazocine is as safe and effective in controlling postoperative pain of moderate severity as other commonly used analgesics.