Study Objective: To evaluate the effectiveness of nicardipine and nitroprusside for breakthrough hypertension following carotid endarterectomy, Design: Prospective, randomized, double-blind controlled effectiveness trial. Setting: University-based surgical intensive care unit. Patients: GO ASA physical status I; II, III, and IV patients experiencing breakthrough hypertension at the time of admission to the intensive care unit (ICU). Interventions: Patients received either nicardipine (n = 29) and placebo or nitroprusside (n = 31) and placebo for up to 6 hours postoperatively, Loading doses of nicardipine were provided, but placebo was wed as a load for patients randomized to nitroprusside. Measurements and Main Results: Rapidity and variability of blood pressure (BP) control were assessed. During the first 10 minutes, 83% of nicardipine patients compared to 23% of nitroprusside-treated patients, achieved BP control (p < 0.01). Following initial control, 12 nicardipine- and 24 nitroprusside-treated patients required additional titration of their infusions to maintain blood pressure within the targeted range (p < 0.05). No patient suffered a stroke, myocardial infarction, or was returned to the operating room (OR) for bleeding. Conclusions: Nicardipine administration produced more rapid BP control, most likely related to the administration of a loading dose. In addition to more rapid control, nicardipine-treated patients had less variability in BP and required significantly fewer additional interventions. Although no patient suffered a major event during this study, this study was not powered sufficiently to assess safety. (C) 2001 by Elsevier Science Inc.