A Meta-Analysis of the Utility of Preoperative Intravenous Paracetamol for Post-Caesarean Analgesia

Background and objectives: Worldwide, the number of caesarean sections performed has increased exponentially. Some studies have reported better pain control and lower postoperative requirements for opioids when intravenous (IV) paracetamol was administered preoperatively. This meta-analysis thus aimed to investigate the utility of preoperative IV paracetamol for post-caesarean analgesia. Materials and Methods: By using the keywords (paracetamol OR acetaminophen) AND [cesarea* OR caesarea* OR cesaria* OR caesaria*], a systematic literature search was conducted using PubMed, Medline, Embase, Google Scholar and ClinicalTrials.gov databases for papers published in English between January 1, 1960 and March 1, 2019. Grey literature was searched as well. Results: Seven clinical trials were reviewed, while five randomized, placebo-controlled, double-blind studies were included in the final meta-analysis. Applying per-protocol analysis and a random-effects model, there was a significant reduction in postoperative opioid consumption and pain score in the group that received preoperative IV paracetamol, compared to placebo, as the standardized mean difference (SMD) were -0.460 (95% CI -0.828 to -0.092, p = 0.014) and -0.719 (95% CI: -1.31 to -0.13, p = 0.018), respectively. However, there was significant heterogeneity amongst the different studies included in the meta-analysis (I² = 70.66%), perhaps owing to their diverse protocols. Some studies administered IV paracetamol 15 min before induction while others gave it before surgical incision. Conclusion: This is the first review on the topic. Overall, preoperative IV paracetamol has convincingly demonstrated useful opioid-sparing effects and it also appears safe for use at the time of delivery. It should be considered as a component of an effective multimodal analgesic regimen. Future studies could be conducted on other patient groups, e.g., those with multiple comorbidities or chronic pain disorders, and further delineate the optimal timing to administer the drug preoperatively.