The exact mechanism of action has not yet been deciphered. What is certain is the inhibition of the enzyme cyclooxygenase, which is essential for the development of pain. However, researchers suspect that opioid and 5-HT receptors are additional targets of the drug, which may also influence pain perception to a certain extent.
Metamizole is used exclusively as the sodium salt metamizole sodium. This makes it possible to administer the substance as a tablet. The half-life of metamizole is very short. It is metabolized in the liver and the bioavailability is about 90%. The plasma half-life is about 2.5 hours. Excretion occurs through the kidneys.
Concomitant administration with chlorpromazine should be avoided as dangerous hypothermia may result.
In combination with methotrexate, liver damage may occur.