metamizole sodium

thumb|Oral solution bottle of dypirone in its packaging (Portuguese lettering) Metamizole or dipyrone (informally known as the "Mexican aspirin") is a painkiller, spasm reliever, and fever reliever drug. It is most commonly given by mouth or by intravenous infusion. It belongs to the ampyrone sulfonate family of medicines and was patented in 1922. Metamizole is marketed under various trade names. It was first used medically in Germany under the brand name "Novalgin", later becoming widely known in Slavic nations and India under the name "Analgin".

Sale of Metamizole is restricted in some jurisdictions following studies in the 1970s which correlated it to severe adverse effects, including agranulocytosis. Other studies have disputed this judgement, instead claiming that it is a safer drug than other painkillers. Metamizole is popular in many countries, where it is typically available as an over-the-counter medication.