The Label Has Not Moved Since 1996
A short read on stroke thrombolysis (treatment that dissolves the clot causing the stroke) and the question that decides most opinions written about it. A composite of cases I see repeatedly, with no detail drawn from any actual matter.
An expert report lands on your desk. It concerns a patient treated with alteplase three hours and forty minutes after the last known well time, and it says the treatment fell outside the approved indication. The report cites the drug label, which does say three hours. It has said three hours since June 1996, and it says three hours today.
Is the report right? It is accurate about the label but wrong about the standard of care.
The two have not agreed for nearly two decades. The ECASS III trial found benefit between three and 4.5 hours in 2008, and guideline practice followed. The 2026 AHA/ASA guideline goes further, collapsing the separate three-hour and 3-to-4.5-hour recommendations that organized the 2019 edition into a single Class 1 recommendation across the whole 4.5-hour window. Eligibility still turns on whether the deficit is disabling, and faster is still better inside the window. Treatment at three hours and forty minutes sits squarely inside it. The Food and Drug Administration label was never revised to match, so the same treatment is guideline-supported and off-label at the same time.
Is that an exotic edge case? It is the ordinary condition of this drug, and it runs in both directions.
Consider the mirror image. Another report criticizes a hospital for withholding treatment from a patient over eighty, citing the ECASS III exclusion criteria. These criteria, such as age above eighty, an NIHSS score above twenty-five, use of any oral anticoagulant, and a prior stroke with diabetes, were the trial's entry criteria. They were the conditions under which that study recruited, not a definitive list of harms. Treating them as absolute bars is among the most common analytical errors in this area.
So the question underneath almost every thrombolysis opinion is narrower than it first appears. Not what the evidence supports now. What was established practice on the date of the event, and which document does the opinion actually rest on?
Three things follow for a reviewer. An opinion anchored to the drug label alone is anchored to 1996. An opinion citing a guideline should name the edition, because there are several, each supersedes the last, and the current one already carries a published correction. And an opinion applying today's eligibility rules to a chart from 2011 makes the same mistake as one applying 2011 rules to a chart from last year, only in the opposite direction.
Part II, on where the decision itself fails, follows on 15 August.
Tobias B. Kulik, MD, FAAN, CIME/ABIME, CPPS
CorteXion LLC · Scientia et Veritas
The Primer in this month's Writings
Thrombolysis for Stroke, Part I: What the Drug Does and How the Window Moved — cortexion.co/writings/iv-thrombolysis-primer-part-1
Primary source
Prabhakaran S, Gonzalez NR, Zachrison KS, et al. 2026 Guideline for the Early Management of Patients With Acute Ischemic Stroke: A Guideline From the American Heart Association/American Stroke Association. Stroke. 2026;57:e316–e436. doi:10.1161/STR.0000000000000513
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