Agranulocytosis and other consequences due to use of illicit cocaine contaminated with levamisole

Purpose of review Most of the illicit cocaine consumed in the United States and elsewhere is contaminated with levamisole, a veterinary medication. Agranulocytosis caused by levamisole exposure through cocaine abuse was first described in 2009. Since then, levamisole has also been shown and is known to cause vascular and neurologic complications. In this review, we provide an overview of the medical consequences of exposure to levamisole from adulterated cocaine. Recent findings Within the past year, several new case series have deepened our understanding of the levamisole-agranulocytosis vasculopathy syndrome. The common nature of this exposure has been delineated, cocaine contaminated with levamisole. Significant controversy surrounds the role of granulocyte colony stimulating factor (GCSF) in levamisole-associated agranulocytosis. Summary More than three fourths of cocaine users in the United States are exposed to levamisole; a significant minority of these individuals will develop autoimmune-mediated neutropenia, cutaneous vascular complications, and/or leukoencephalopathy. Levamisole exposure should be considered in the differential diagnosis of patients who present with these conditions in the setting of cocaine abuse. Neutropenia appears to resolve rapidly with cessation of exposure, so that GCSF therapy and a work-up for other causes may not be needed in all patients.