Objective: The authors reviewed the pathogenesis of cocaine-related cerebral ischemia, appraised current knowledge of its sequelae, and assessed the role of putative therapeutic agents, particularly dihydropyridine-class calcium channel antagonists.
Method: The authors performed an OVID-based literature review of all indexed journals between 1966 and 2000.
Results: Cocaine abuse significantly increases the risk of ischemic stroke. The principal mechanism of cocaine-induced cerebral ischemia is vasospasm of large cranial arteries or within the cortical microvasculature. Increased levels of extracellular monoamines, particularly dopamine, mediate vasospasm. Neuroanatomical and labeling studies also have shown that dopamine-innervated neurons may regulate cerebral blood flow. Indeed, dopamine-rich brain regions appear to be relatively specific targets for cocaine-induced cerebral ischemia. Neuroimaging studies show that cocaine-induced hypoperfusion can persist even after 6 months of abstinence. Hypoperfusion can result in deficits on complex and simple psychomotor tasks but perhaps not on memory or attention. Severe cerebral ischemia can directly precipitate neuronal death and degradation, a condition exacerbated by liberation of the excitatory amino acid glutamate. Dihydropyridine-class calcium channel antagonists inhibit cocaine-mediated dopamine release on neurons involved in vasospasm and the control of cortical circulation. Other causes of cerebral ischemia include thrombogenesis and vasculitis. Although antithrombotic agents have potential in alleviating cocaine's neurotoxic effects, their use may be limited by the risk of spontaneous hemorrhage.
Conclusions: Cocaine abuse can result in stroke, neuroischemia, and cognitive deficits that can persist even after prolonged abstinence. Dihydropyridine-class calcium channel antagonists, such as isradipine, show promise as therapeutic agents for preventing cocaine-induced cerebral ischemia.