Final answer:
A patient diagnosed with an ischemic stroke should receive tissue plasminogen activator (tPA) within the first 3 hours of the onset of symptoms to effectively break down the clot and restore blood flow.
Step-by-step explanation:
A patient diagnosed with an ischemic stroke should be treated within the first 3 hours of symptom onset with tissue plasminogen activator (tPA). This is because tPA is a thrombolytic agent that facilitates the breakdown of the abnormal clot that is causing the stroke. By converting plasminogen to plasmin, it restores blood flow to the affected area of the brain, potentially preventing permanent damage. The use of tPA must be promptly administered after confirming the stroke is not hemorrhagic, as the causes and treatments for ischemic versus hemorrhagic strokes are different.