What is the nurse's first action when a patient receiving IV alteplase reports a sudden severe headache?

Choice A reason: A neurologic assessment is essential but should follow immediate discontinuation of alteplase if intracranial hemorrhage is suspected. Choice B reason: Pain assessment is secondary and does not address the potential life-threatening complication of bleeding. Choice C reason: A sudden severe headache during alteplase infusion may indicate intracranial hemorrhage. The infusion must be stopped immediately to prevent further bleeding. Choice D reason: Antihypertensives may be used if blood pressure is elevated, but they are not the first action in response to a suspected hemorrhage.