Agranulocytosis and liver damage associated with pyrazinobutazone with evidence for an immunological mechanism

Agranulocytosis and liver injury is described in a patient with Reiter's syndrome of 3 years duration who received pyrazinobutazone for 6 weeks before the development of the clinical picture reported. Other causes of agranulocytosis and hepatic damage were excluded and a lymphocyte transformation test to the drug revealed significant lymphocyte proliferation in response to the drug. This suggests a hypersensitivity reaction as the mechanism for this previously unrecognized association of adverse effects to pyrazinobutazone.