We see them in the emergency room: people who were going about their normal lives just moments earlier and suddenly cannot speak clearly, move an arm or stand on their feet. From the moment they arrive at the hospital, a race against time begins. Every minute that a blood vessel in the brain remains blocked, millions of nerve cells can suffer irreversible damage. For years, the medication used to dissolve these clots has required an intravenous infusion lasting about an hour. Now, a major change is approaching: a drug called tenecteplase, or TNK, administered through a single intravenous injection in just five to 10 seconds. Already used in several countries, TNK is expected to become available in Israel after completing the local registration process.
As a physician who regularly treats stroke patients, I see this as an important advance. The new medication could simplify a critical stage of emergency treatment, allowing medical teams to focus more quickly on the next steps needed to save brain tissue.
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Every minute counts during a stroke, and delays in treatment can have serious consequences
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A stroke occurs when the blood supply to part of the brain is disrupted. Approximately 90% of cases are ischemic strokes, caused by a blood clot blocking an artery. Without oxygen and nutrients, brain cells begin to deteriorate, producing sudden symptoms such as weakness in an arm or leg on one side of the body, facial drooping, difficulty speaking, vision problems or an unusual loss of balance. One of the main treatments for acute ischemic stroke is thrombolysis, a medication that dissolves the clot and helps restore blood flow. It can be administered only after medical examination and brain imaging, which are essential, among other things, to rule out bleeding in the brain.
Traditionally, thrombolysis has been used within 4.5 hours of symptom onset in eligible patients whose stroke causes disabling symptoms. Updated American guidelines published in January 2026 also support treatment beyond that window in carefully selected patients, including some treated between 4.5 and nine hours after onset, when advanced imaging shows potentially salvageable brain tissue.
For decades, the standard clot-dissolving medication has been alteplase, also known as tissue plasminogen activator, or tPA. It is administered in two stages: an initial dose followed by an intravenous infusion lasting approximately one hour. Alteplase transformed modern stroke medicine, but preparing and managing the prolonged infusion requires equipment, staff attention and additional coordination.
TNK offers a simpler approach. Because of its biological properties, the medication remains active in the body longer, acts more selectively on blood clots and is more resistant to the natural mechanisms that inhibit clot-dissolving activity. Most importantly from an operational perspective, it can be administered in a single injection lasting only five to 10 seconds, without a prolonged infusion.
But convenience alone would not justify changing a treatment that has been used successfully for decades. The crucial question is whether TNK is at least as effective and safe as alteplase. A 2024 meta-analysis published in Neurology, combining 11 randomized controlled trials involving approximately 7,500 stroke patients, found that those treated with TNK had a statistically significant greater likelihood of achieving excellent functional recovery than patients given tPA.
Alteplase, also known as tPA, a clot-dissolving medication used to treat ischemic stroke
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Other major studies have reached similar conclusions, showing that TNK is at least as effective as alteplase and may offer additional benefits for certain patients. Importantly, the risk of symptomatic bleeding in the brain, the most serious complication associated with clot-dissolving treatment, was comparable between the two medications.
The advantages may be particularly important for patients who also need mechanical thrombectomy, an emergency procedure performed when a large artery in the brain is blocked. During thrombectomy, physicians guide a catheter through the blood vessels to the obstruction and physically remove the clot. Some patients receive clot-dissolving medication beforehand, and a single-dose treatment makes the transition to the procedure simpler, without requiring the medical team to manage a continuing hour-long infusion.
A clinical trial involving approximately 200 patients awaiting thrombectomy suggested that TNK's benefits may extend beyond convenience. Among patients who received TNK, 22% experienced substantial restoration of blood flow before the procedure began, compared with 10% of those treated with alteplase. Patients receiving TNK also demonstrated better functional outcomes three months later.
Another important advantage concerns patients admitted to hospitals that cannot perform mechanical thrombectomy and must be transferred elsewhere. This is particularly relevant in Israel, where only some hospitals have the facilities and specialist teams required for the procedure. A large U.S. study published in JAMA Network Open in July 2026 examined data from more than 133,000 stroke patients and found that TNK was associated with shorter treatment times after hospital arrival and faster transfers for patients requiring care at another medical center. Those minutes can be critical when brain tissue is deprived of blood.
These findings are especially significant given the relatively limited use of clot-dissolving treatment in Israel. According to the Health Ministry's latest national stroke registry report, more than 16,000 cases of stroke and transient ischemic attack were reported in 2023, yet only about 11% of patients with ischemic stroke received thrombolytic treatment.
Facial asymmetry caused by stroke
(Photo: shutterstock)
In March 2025, the U.S. Food and Drug Administration approved tenecteplase for treating acute ischemic stroke in adults, following years in which it had been approved in the United States for treating heart attacks. The American Heart Association and American Stroke Association subsequently incorporated TNK into their updated January 2026 guidelines, recognizing it as an alternative to alteplase for eligible patients.
Israel is moving in the same direction. In a position paper published in August, the Israeli Stroke Society recommended preparing for a transition to TNK as the preferred thrombolytic treatment once the drug completes its registration process. According to the document, registration is expected to be completed around the beginning of 2027, after which TNK could gradually replace the older medication.
It is important to understand what the new drug does and does not change. TNK does not eliminate the need for urgent medical assessment, brain imaging or mechanical thrombectomy when required. Nor is it suitable for every patient with stroke symptoms. It simplifies one crucial stage in a complex chain of emergency care, where delays can have lasting consequences.
Dr. Rom MandelThe fundamental principle of stroke medicine remains unchanged: time is brain. Even the most advanced medication cannot help a patient who arrives too late to receive appropriate treatment. Recognizing the warning signs and seeking emergency medical care immediately are therefore just as important as improvements in the medications themselves. If someone suddenly develops facial weakness, difficulty speaking, weakness on one side of the body or an unexplained loss of balance, there is no time to wait and see whether the symptoms disappear. Emergency medical services should be called immediately.
Israeli Health Ministry data illustrate the importance of arriving by ambulance. In 2023, ischemic stroke patients transported to the hospital by ambulance were 2.2 times as likely to receive clot-dissolving treatment as those who arrived by other means. Yet only about half of stroke patients reached the hospital by ambulance.
Tenecteplase has the potential to make stroke treatment faster and easier for medical teams, and possibly improve recovery for some patients. But even as new medications change what happens inside the hospital, the most important message remains the same: the sooner a stroke patient receives appropriate treatment, the greater the chance of saving brain tissue, reducing disability and returning to an independent life.
- Dr. Rom Mandel is director of the Stroke Service in the Neurology Department at Assuta Ashdod Public Hospital