métamizole

Metamizole, also known as dipyrone or novalgin, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and fever. It is available by prescription in many countries, but its use is restricted or banned in others due to a rare but serious side effect called agranulocytosis, a severe drop in white blood cells.

The mechanism of action of metamizole is not fully understood but is believed to involve inhibition of cyclooxygenase (COX) enzymes, which are involved in the production of prostaglandins, substances that mediate pain and fever. It also has effects on the central nervous system. Metamizole is administered orally, intravenously, or intramuscularly.

It is effective in treating moderate to severe pain, including postoperative pain, colic, and cancer pain. It is also used to reduce high fever that does not respond to other antipyretics. Due to the risk of agranulocytosis, metamizole is typically reserved for situations where other pain relievers are ineffective or contraindicated.

Side effects, besides agranulocytosis, can include allergic reactions, gastrointestinal disturbances, and a drop in blood pressure. Monitoring blood counts is often recommended during treatment. The availability and regulatory status of metamizole vary significantly by country, reflecting ongoing debates about its risk-benefit profile.