Metamizole (Dipyrone) as an Alternative Agent in Postoperative Analgesia in Patients with Contraindications for Nonsteroidal Anti-Inflammatory Drugs.

PURPOSE Nonsteroidal anti-inflammatory drugs (NSAIDs) play an important role in multimodal pain management. In patients with a contraindication for NSAIDs, pain management is challenging. A recent Dutch anesthesiology guideline propagates the use of metamizole (dipyrone) in these patients. Metamizole is a controversial drug, its use being previously discouraged because of the risk for agranulocytosis. We discuss whether metamizole could be an alternative to classical NSAIDs and opioids in postoperative pain management despite this drawback. METHOD Literature review and pharmacovigilance research based on World Health Organization adverse effect registrations. RESULTS Metamizole causes fewer gastric and duodenal ulcers than other nonselective NSAIDs, and the risk for bleeding is limited. It is unknown whether it is safer than a nonselective NSAID combined with a proton pump inhibitor. Although the drug appears to be safe for renal function in healthy volunteers, data in high-risk patients (eg, those with heart or renal failure) are lacking. The incidence of metamizole-induced agranulocytosis is controversial, but the risk is likely to be limited with short-term postoperative use in this selected group of patients. CONCLUSION Although firm evidence is lacking, metamizole may be safer for the upper intestinal tract and kidneys than other NSAIDs, and could alternatively be used in patients with an increased risk for stomach or renal problems. Hereby, improved postoperative pain relief can potentially be achieved. The risk for metamizole-induced agranulocytosis is judged to be acceptable.