Paracetamol is an effective drug to use for pain following oral surgery

Studies were identified using the Cochrane trials registers of the Oral Health Group and of the Pain, Palliative and Supportive Care Group, along with the Cochrane Central Register of Controlled Trials, Medline, Embase and the Current Controlled Trials Register. Handsearching included several dental journals as well as the bibliographies of relevant clinical trials and review articles for studies outside the journals searched by hand. Authors of the randomised controlled trials (RCT) identified and manufacturers of analgesic pharmaceuticals were contacted in an attempt to identify unpublished or ongoing RCT. No language restriction was applied.

Randomised, parallel-group, placebo-controlled, double-blind clinical trials of paracetamol (acetaminophen) for acute pain following third molar surgery were included.

All trials identified were scanned independently and in duplicate by two review authors. Any disagreements were resolved by discussion or, if necessary, a third review author was consulted. The proportion of patients who recorded at least 50% pain relief was calculated for both paracetamol and placebo. The number of patients experiencing adverse events, and/ or the total number of adverse events reported were analysed.

Twenty-one trials met the inclusion criteria. A total of 2048 people were initially enrolled in the trials (1148 took paracetamol and 892 the placebo) and of these 1968 (96%) were included in the meta-analysis (1133 took paracetamol, and 835 the placebo). Paracetamol provided a statistically significant benefit when compared with placebo for pain relief and for pain intensity at both 4 and 6 h. Most studies were found to have moderate risk of bias, with poorly reported allocation concealment being the main problem. The risk ratio for pain relief at 4 h was 2.85 (95% confidence interval, 1.89-4.29), and at 6 h was 3.32 (95% confidence interval, 1.88-5.87). A statistically significant benefit was also found between doses of <1000 mg and of 1000 mg, the higher dose giving greater benefit for pain relief and intensity at both timepoints. There was no statistically significant difference between the number of patients who reported adverse events: this was 19% in the paracetamol group and 16% in the placebo group.

Paracetamol is an effective drug to use for postoperative pain following oral surgery, and the reporting of adverse events shows it to be a safe drug: the number-needed-to-treat (NNT) to benefit is three for 1000 mg of paracetamol at 6 h and the NNT to harm is 33. It is most effective at a 1000 mg dose, and can be taken at 6-hourly intervals without compromising safety. It could be considered more readily by dentist and patients both as a first-choice analgesic, or to be taken alternately with other analgesics such as nonsteroidal anti-inflammatory drugs.