[Acute drug-induced agranulocytosis: experience of the Regional Center of Pharmacovigilance of Lyon over 7 years].

Sixty-two cases of drug-induced agranulocytosis, spontaneously reported to the regional drug monitoring centre in Lyon from 1988 to 1994, have been analysed. The mean age of patients was 58.6 years, and sex ratio was 1:1. The mean delay of onset was 46.2 days and absolute neutrophil counts (ANC) dropped below 0.1 x 10(9)/l in 73 per cent of patients. Bone marrow aspirates disclosed absence of myeloid series in 28 per cent of investigated cases. Neutrophil recovery occurred after a mean of 9.3 days, and the overall fatality rate was 6.5 per cent. Haematopoietic growth factors (HGF) were used in 11 patients with an ANC below 0.1 x 10(9)/l and/or a hypoplastic bone marrow. We have found no clear indication for a potential benefit of HGF treatment, but HGF were usually administered late during the course of neutropenia, i.e., after a mean of 6 days. The incidence rate estimated for people living in the Rhône administrative division was 3.3 per million per year, similar to that found in epidemiological studies. Drugs most frequently involved were anti-infective agents and psychotropic drugs.