Treatment of hypertension with isradipine reduces infarct size following stroke in laboratory animals.

Earlier studies have shown isradipine to reduce the size of infarct in a rat model of embolic stroke (permanent occlusion of the left middle cerebral artery) (Sauter A, Rudin M: Stroke 1986; 17: 1228-1234). The greater the delay in isradipine administration after occlusion of the left middle cerebral artery, the less these effects until no effect on infarct size was obtained when isradipine was injected six hours after occlusion of the left middle cerebral artery. Blood pressure was dose-dependently reduced in spontaneously hypertensive rats (blood pressure more than 200 mm Hg), which received injections of isradipine subcutaneously 2.5, 5, and 10 mg/kg per day for six days, to approximately 150, 135, and 120 mm Hg, respectively. Twelve hours post-injection, the left middle cerebral artery was occluded. Isradipine also dose-dependently decreased infarct size, as measured by magnetic resonance imaging at 24 hours and histology five days later, by approximately 20, 40, and 60 percent, respectively, compared with vehicle-injected controls. These results suggest that isradipine, at doses required to normalize the high blood pressure in spontaneously hypertensive rats, will substantially reduce the infarct size caused by a later stroke.