Which medication should not be given 12-24 hours after symptom onset?

RTPA, or recombinant tissue plasminogen activator, is a thrombolytic medication typically used to dissolve blood clots in patients experiencing an acute ischemic stroke. The administration of RTPA is most effective when given as soon as possible after symptom onset, ideally within a three-hour window but can be extended to a maximum of 4.5 hours. Beyond this period, the risks associated with administering RTPA increase due to the potential for serious complications, such as hemorrhagic transformation of the infarcted brain tissue.

Unlike RTPA, the other medications listed do not have the same strict time constraints related to symptom onset. Plavix, an antiplatelet drug, is useful for preventing further clotting and can be started after the initial treatment of an acute ischemic event. Atrovent, an anticholinergic bronchodilator, and propranolol, a beta-blocker used for various cardiovascular conditions, do not have similar timing limitations regarding their administration after the onset of symptoms. Therefore, RTPA should not be given 12-24 hours after symptom onset because its effectiveness significantly declines, increasing the risk of adverse effects.