A nurse admits a client who has a subarachnoid hemorrhage and expects to administer medication to decrease intracranial pressure (ICP). Which of the following medications should the nurse administer?

Choice A rationale Phenytoin is an anticonvulsant medication used to prevent and control seizures, which can be a complication of subarachnoid hemorrhage. However, it does not directly decrease intracranial pressure. Its primary mechanism is to stabilize neuronal membranes and reduce abnormal electrical activity. Choice B rationale Nicardipine is a calcium channel blocker used to manage hypertension and prevent vasospasm in subarachnoid hemorrhage. While managing blood pressure is crucial, nicardipine's direct action is on vascular smooth muscle to cause vasodilation, not to directly reduce intracranial pressure. Choice C rationale Mannitol is an osmotic diuretic that functions by creating an osmotic gradient, drawing water from brain tissue into the intravascular space. This reduction in cerebral edema directly decreases intracranial pressure, making it a primary medication for managing elevated ICP in subarachnoid hemorrhage. Choice D rationale Dopamine is a vasopressor medication used to increase blood pressure and improve cardiac output, often in shock states. While maintaining cerebral perfusion pressure is important, dopamine's direct action does not lower intracranial pressure; in some cases, it could potentially increase cerebral blood volume.