A new studysuggests that the traditional three-hour time window for administering a potent clot-busting medication is too short. Findings published in the journal Stroke show treatment of tissue plasminogen activator or tPA can benefit patients up to 4.5 hours. tPA can open blocked blood vessels and help restore blood flow to the brain. The FDA has not approved tPA for use more than three hours after the onset of symptoms. Physicians can offer the treatment to patients as an “off-label” use after carefully explaining the risks and benefits. Every minute you wait, your chances of getting better from the treatment diminish.