Safety Study of Nicardipine to Treat Cerebral Vasospasm

Subarachnoid hemorrhage accounts for approximately 5% of all strokes and affects 30,000 Americans per year. Poor outcome from aneurysmal subarachnoid hemorrhage (SAH) occurs in 50 to 75% of patients, and this is attributed to secondary ischemia in approximately 30% of patients. This delayed cerebral ischemia has been attributed to the anatomic narrowing of arteries in the cerebral vasculature which occurs following SAH. Because of this relationship between cerebral vasospasm, cerebral ischemia, and poor outcome, there has been significant effort to establish treatments that decrease the incidence of vasospasm after SAH. Currently, medications and hemodynamic maneuvers are used as standard of care for the treatment of vasospasm and to improve outcome after SAH. The calcium channel blocker, nimodipine, is one of the few treatments for vasospasm that has been shown to be of proven benefit. Nicardipine is another calcium channel blocker that has been evaluated in several studies via an intravenous administration route. These studies did show significant improvements in symptomatic and angiographic vasospasm, although a benefit in outcome was not seen. However, the intravenous administration of nicardipine was associated with significant systemic side effects that may have affected outcome including hypotension, pulmonary edema, and azotemia. The administration of nicardipine via an intrathecal route avoids the systemic complications associated with intravenous dosing since the direct cerebrospinal fluid dosing is much lower. The result is that the systemic concentration will remain low avoiding systemic side effects, and central nervous system concentration will remain high. We propose that this difference may improve outcomes while minimizing complication related effects on patient outcomes.