RESUMO
OBJECTIVE: Quinine is a drug which is mainly used for prevention of nocturnal leg cramps. Serious side effects of this drug have been described in recent years, including cytopenias and the hemolytic-uremic syndrome. We report seven cases of severe adverse effects of quinine. MATERIAL AND METHODS: Seven patients who were hospitalized with adverse effects of quinine during the period 1978-2000 are described. Medical records were reviewed with respect to clinical and laboratory features. Serum samples from three patients were tested for quinine-dependent antibodies against platelets and/or granulocytes by flow cytometry. RESULTS: All patients were females aged 52 to 79 years, who were taking quinine for nocturnal leg cramps. Five of the patients experienced recurrent episodes of fever, chills, nausea and vomiting, and three had abdominal pain as well. Two of these patients had pancytopenia, one of whom had evidence for disseminated intravascular coagulation. One had leukopenia and thrombocytopenia. Two patients developed hemolytic-uremic syndrome associated with disseminated intravascular coagulation. One of them suffered irreversible renal failure requiring maintenance hemodialysis. One year later she underwent successful kidney transplantation. All patients had taken quinine several hours prior to the onset of symptoms. In two cases the clinical findings were reproduced by the administration of quinine. Quinine-dependent IgG antibodies against platelets were detected in two patients and against granulocytes in one patient. CONCLUSIONS: These cases illustrate the severe adverse effects that can be caused by quinine. Five patients had solid evidence for side effects of quinine being the cause of their illness and strong suggestions of association with the drug were present in two patients. In view of potentially life-threatening side effects, it appears prudent to prohibit the availability of quinine over the counter. Furthermore, it is important that physicians thoroughly consider the indication for each prescription of quinine and remain vigilant toward its side effects.