Effect of high-dose methylprednisolone on vasospasm after subarachnoid hemorrhage.

The effects of high-dose methylprednisolone (MP) on vasospasm following subarachnoid hemorrhage (SAH) were investigated. In a double hemorrhage canine model, administration of high-dose MP (10 mg/kg, every 12 hours) reduced angiographic narrowing of the basilar artery and prevented morphological changes in the arterial wall. In addition, increased platelet aggregation observed from days 4 to 7 in untreated SAH dogs was inhibited by the MP treatment. An in vitro experiment showed that MP inhibited platelet aggregation dose-dependently. High-dose MP had a nonspecific vasodilatory effect on the smooth muscle of the basilar artery. In another SAH model with dysautoregulation of cerebral blood flow (CBF), intravenous MP administration markedly attenuated the decrease in both blood pressure and CBF caused by exsanguination. These results indicate that MP has beneficial effects in normalizing CBF dysautoregulation following SAH. High-dose MP has several advantages for preventing and improving the multiple pathological status in cerebral vasospasm following SAH.