Abstract: We included 25 trials with 2505 participants randomised to the different pharmacological agents and inactive controls. All the trials were at unclear risk of bias. Most trials included only low anaesthetic risk people undergoing elective laparoscopic cholecystectomy. Participants were allowed to take additional analgesics as required in 24 of the trials. The pharmacological interventions in all the included trials were aimed at preventing pain after laparoscopic cholecystectomy. There were considerable differences in the pharmacological agents used and the methods of administration. The estimated effects of the intervention on the proportion of participants who were discharged as day-surgery, the length of hospital stay, or the time taken to return to work were imprecise in all the comparisons in which these outcomes were reported (very low quality evidence). There was no mortality in any of the groups in the two trials that reported mortality (183 participants, very low quality evidence). Differences in serious morbidity outcomes between the groups were imprecise across all the comparisons (very low quality evidence). None of the trials reported patient quality of life or time taken to return to normal activity. The pain at 4 to 8 hours was generally reduced by about 1 to 2 cm on the visual analogue scale of 1 to 10 cm in the comparisons involving the different pharmacological agents and inactive controls (low or very low quality evidence). The pain at 9 to 24 hours was generally reduced by about 0.5 cm (a modest reduction) on the visual analogue scale of 1 to 10 cm in the comparisons involving the different pharmacological agents and inactive controls (low or very low quality evidence). There is evidence of very low quality that different pharmacological agents including non-steroidal anti-inflammatory drugs, opioid analgesics, and anticonvulsant analgesics reduce pain scores in people at low anaesthetic risk undergoing elective laparoscopic cholecystectomy. However, the decision to use these drugs has to weigh the clinically small reduction in pain against uncertain evidence of serious adverse events associated with many of these agents. Further randomised clinical trials of low risk of systematic and random errors are necessary. Such trials should include important clinical outcomes such as quality of life and time to return to work in their assessment.

Plain-language summary: We identified 25 randomised clinical trials involving 2505 people undergoing laparoscopic cholecystectomy. Most participants in the trials were low anaesthetic risk people undergoing planned laparoscopic cholecystectomy. The choice of whether the participants received the different painkillers (or not) was determined by a method similar to the toss of coin so that the treatments compared were conducted in people who were as similar as possible. The treatments in all the included trials were aimed at decreasing the pain after laparoscopic cholecystectomy before the participants reported pain. Participants were allowed to take additional painkillers as required in most of the trials. There were no deaths in either group in three trials (183 participants) that reported deaths. The differences in the serious complications between the groups was imprecise in all the comparisons. None of the trials reported quality of life or the time taken to return to normal activity. The differences in length of hospital stay and the time taken to return to work was imprecise in all the comparisons that reported these. Pain was lower in the participants who received painkillers compared with those who received controls at 4 to 8 hours and at 9 to 24 hours as measured by the visual analogue scale (a chart that rates the amount of pain on a scale of 1 to 10). This is a modest reduction and is comparable to other methods of pain reduction such as administering local anaesthetics (drugs that numb part of the body, similar to the ones used by the dentist to prevent the people from feeling pain) during the operation. In summary, different painkillers reduce pain scores in low anaesthetic risk people undergoing elective laparoscopic cholecystectomy. However, the decision to use these drugs has to weigh the clinically small reduction in pain against uncertain evidence of serious adverse events associated with many of these agents. The overall quality of evidence was very low. Further trials are necessary. Such trials should include outcomes such as quality of life, the time taken to return to normal activity, and the time taken to return to work, which are important for the person undergoing laparoscopic cholecystectomy and the people who provide funds for the treatment.