Acute renal failure and severe thrombocytopenia associated with metamizole.

Metamizole or dipyrone is a pyrazolone derivative that belongs to the non-steroidal anti-inflammatory drugs. Its main side-effect is hematological toxicity. Thrombocytopenia due to metamizole is rare and is usually associated with the involvement of the two other blood series. Drug-induced thrombocytopenia is more frequently related to immune mechanisms, and the diagnosis is still largely made by exclusion of other causes and by correlation of timing of thrombocytopenia with the administration of drug. Metamizole may cause acute renal failure due to hemodynamic renal failure/acute tubular necrosis and/or acute tubulointerstitial nephritis. We report a case of acute renal failure and severe thrombocytopenia after metamizole. As far as we know, this combination of adverse effects from this drug has not been reported previously.