Objective: To report a case of aplastic anemia in a patient treated with cyanamide, an alcohol-aversive drug. A 67-year-old man was admitted to hospital because of fever and pancytopenia. He had taken cyanamide for 6 months as an alcohol deterrent. No other risk factors for aplastic anemia were identified by interviewing the patient using a structured validated questionnaire. The results of bone-marrow biopsy showed severe aplastic anemia. Cyanamide was discontinued and the patient was treated according to a prespecified treatment protocol. One year after hospital admission, the patient was completely recovered with no need of immunosuppressive therapy. An objective causality assessment revealed that an adverse drug reaction was probable.
Discussion: As the efficacy of cyanamide has been questioned, due to the failure of various trials to show any benefit over placebo, its overall benefit/risk ratio should be reconsidered. The complete and rapid hematological recovery after discontinuation of the drug, and the absence of other factors that could explain the condition support the association of the present case of aplastic anemia with cyanamide. The mechanism remains unknown. Aplastic anemia is a rare but potentially serious adverse drug effect of cyanamide treatment.
Conclusions: Given the poor evidence on the efficacy of cyanamide and the associated risk of aplastic anemia, its use in reducing alcohol consumption should be reconsidered.