Reliable evidence for efficacy of single dose oral analgesics

Data sourcesThe Cochrane library was searched for Cochrane systematic reviews.Study selectionCochrane reviews on single pain medications for the treatment of acute pain were included. Non-Cochrane reviews were included for tramadol.Data extraction and synthesisTwo reviewers independently searched, selected reviews for inclusion, assessed quality and performed data extraction. A protocol in case of disagreement was in place. Data were collected on number of included studies and participants, drug, dose and formulation and pain model. The authors concentrated on the amount of information and the potential for publication bias.Pain relief was calculated using at least 50% maximum pain relief, as a percentage, and as NNTs. Duration of analgesia was measured as mean or median and time to remedication was calculated as percentage of patients.ResultsThirty-nine reviews including 41 interventions were analysed and NNTs for at least 50% maximum pain relief were summarised in a graphic. NNTs range from almost one all the way to five. Only one intervention, codeine 60, had an NNT ≥10. Results judged to be reliable were listed in detail. Mean or median time to remedication was also presented in a graphic.The authors conclude that there is a great amount of quality information on single dose analgesics, and highlighted the potential benefit of fast acting formulations and fixed formulations to achieve good long-lasting analgesia.ConclusionsThere is a wealth of reliable evidence on the analgesic efficacy of single dose oral analgesics. Fast acting formulations and fixed dose combinations of analgesics can produce good and often long-lasting analgesia at relatively low doses. There is also important information on drugs for which there are no data, inadequate data, or where results are unreliable due to susceptibility to publication bias. This should inform choices by professionals and consumers.