Stroke experts have widened the window for when the clot-busting drug tPA can be given intravenously. The previous U.S. guideline was to give the drug only if treatment could be started within three hours of the onset of symptoms. Many patients did not get the drug because they didn’t get to the hospital in time or it took too long to do tests to make sure the drug could be helpful. (Everyone with stroke symptoms has to have a CT scan to make sure the stroke is not caused by bleeding in the brain, because if tPA is given on top of bleeding, it could worsen the hemorrhage or even kill the patient.)
The new guideline widens the effective time window to four and one-half hours after symptoms start. It comes from the American Heart Association/American Stroke Association and is based on European studies.
Stroke experts stress that just because there is more time now to administer this drug does not mean patients or doctors should think they can go slow. The faster treatment is begun, the more likely it is to help break up the clot and restore normal blood flow in the brain. Anyone with stroke symptoms needs to be rushed to a hospital with special expertise in stroke treatment.