Patients with ischemic stroke have a window of opportunity for therapeutic intervention to restore regional cerebral blood flow and salvage ischemic brain tissue. The ischemic penumbra is the region with reduced regional cerebral blood flow and viable tissue, which is at risk for irreversible damage over 6 to 9 hours. Because some degree of blood flow is still maintained by collateral circulation, the ischemic penumbra remains viable for hours. However, because of impaired regional autoregulation, this area becomes at risk of ischemic injury when BP decreases,even at more risk when the BP falls rapidly.6 For this reason, lowering the systemic BP pharmacologically in acute ischemic stroke may have disastrous consequences and a cautious approach to managing BP in the first 72 hours is very important.