Metamizole: Current status of the safety and efficacy

Metamizole is a nonsteroidal anti-inflammatory drug, with analgesic, antipyretic, spasmolytic, and weak anti-inflammatory properties. The analgesic effect of metamizole seems to be based on the inhibition of cyclooxygenase enzyme activity and stimulation of cannabinoid receptors. Its use is still controversial, mainly due to agranulocytosis, metamizole-induced serious adverse reaction. While in many countries it is withdrawn from the market, in some countries metamizole is available as a medication prescribed for strictly defined indications, while in the others like Mexico, Brazil and China it can be obtained as an Over-The-Counter drug. The most common adverse effects of metamizole are the skin and subcutaneous tissue disorders. Metamizole appears to be of similar efficacy to analgesics which are frequently used in the treatment of moderate to severe postoperative pain