Metamizole is an active substance belonging to the pyrazolone group with analgesic, antipyretic, and antispasmodic properties. It is administered as a second-line agent for the treatment of severe pain and high fever, and is generally taken up to four times daily. The mechanism of action has not been fully elucidated. Possible adverse effects, which may occur rarely, include hypersensitivity reactions, hypotension, skin rashes, renal function impairment, blood dyscrasias, and injection site reactions. Life-threatening agranulocytosis occurs very rarely. Metamizole may cause red discolouration of the urine due to a metabolite.
Metamizole (ATC N02BB02) has analgesic, antipyretic, and antispasmodic (spasmolytic) properties. The mechanism of action has not been fully elucidated. Both central and peripheral sites of action are discussed. Possible drug targets include cyclooxygenases and cannabinoid receptors. Metamizole is not classified among the non-steroidal anti-inflammatory drugs (NSAIDs) but is generally categorised as a (non-acidic, non-opioid) analgesic and a pyrazolone derivative.
