Tenecteplase (TNK) is a medication that can break down blood clots after a stroke. The Food and Drug Administration (FDA) has not yet approved it for this use, but research shows that it may be effective.

Ischemic stroke is a life threatening condition in which a blood clot blocks the blood supply to the brain. Urgent treatment is necessary to limit brain damage, preserve as much function as possible, and save an individual’s life after a stroke.

Breaking down the blood clot by thrombolysis, or using “clot-busting” medications, may be effective if a person receives it quickly.

TNK is one of two clot-busting drugs that individuals may receive after a stroke. However, its primary use is as a treatment for some types of heart attacks, and its use in people after strokes is relatively recent.

This article explains TNK, how doctors administer it, and the risks.

Closeup of a medical professional injecting medication.Share on Pinterest
FS Productions/Getty Images

TNK is part of a class of thrombolytic medications called tissue plasminogen activators (tPAs). These specialize in breaking down blood clots that develop inside blood vessels. TNK is a modified version of alteplase, another tPA.

The FDA has only approved TNK to treat heart attacks. However, the medication is becoming more common as an off-label treatment for acute ischemic strokes.

Off-label medications are drugs with FDA approval for different uses that doctors may prescribe for purposes other than their approved use.

TNK is a version of natural tPAs already present in the body with altered DNA. It works by attaching to fibrin, a protein in blood clots that shrinks them and allows blood to flow past.

The medication then triggers a natural process that breaks the clot down and helps restore typical blood flow.

A 2023 study concluded that receiving TNK within 4.5 to 24 hours of the start of stroke symptoms could be safe and feasible.

Trials are ongoing to establish the time window that produces the most favorable outcomes.

Doctors administer TNK through a single intravenous dose into the veins, which takes 5 to 10 seconds.

A person receives a dose of 0.25 milligrams per kilogram of body weight, up to a maximum of 25 mg.

The risks and side effects of TNK are similar to those of other thrombolytics. The most common risk is bleeding anywhere in the body.

Existing blood clots may also break off and block a blood vessel in the body, in a complication known as thromboembolism.

People taking TNK may also have a risk of irregular heart rhythms or severe allergic reactions to the medication.

TNK is an altered version of alteplase. However, according to a 2024 systematic review, TNK may be equivalent to alteplase as a treatment and might have several advantages over it:

  • TNK stays active for longer than alteplase in the body.
  • TNK targets blood clots more effectively and precisely than alteplase.
  • Substances in the body that may block the effects of tPA medications are less likely to interfere with TNK than alteplase.
  • TNK may be more cost effective than alteplase.

A 2023 study involving data from over 59,000 people found that people who received TNK after a stroke had an 8.2% mortality rate compared with 9.8% in those using alteplase.

However, a 2023 review suggests that no phase 3 clinical trial has demonstrated that TNK is more effective than alteplase. That said, the authors also stated that it might achieve similar effects with a single dose and at less expense.

More research is necessary to better understand the benefits and reliability of TNK as a stroke treatment.

Alteplase is the only tPA with FDA approval specifically for ischemic stroke treatment.

Trials are ongoing as to whether TNK may become a leading treatment for stroke. However, tPA medications first received approval in 1987 as a heart attack treatment only, before the FDA approved expanding their use to strokes in 1996.

TNK could follow the same journey should clinical trials support its use.

What is the difference between tPA and TNK?

Tissue plasminogen activator (tPA) medications are a class of drugs, whereas tenecteplase (TNK) is a specific medication. In other words, TNK is a type of tPA. tPA is also a natural substance in the body that TNK mimics.

What is the TNK dose for treating a stroke?

The FDA has not yet approved a specific dose of TNK for stroke treatment. However, a 2023 article suggests that a dosage of 0.25 milligrams (mg) per kilogram of body weight, up to a maximum of 25 mg, may be suitable.

How long does TNK last?

The active ingredients of TNK have a half-life of 20 to 25 minutes. This means that around half of the original dosage will be active after this time.

When should a person not receive TNK?

Doctors do not recommend TNK for people with the following: internal bleeding; uncontrolled and very high blood pressure; recent spine or brain surgery; recent head trauma; any conditions that mean the risk of bleeding is higher; or a history of aneurysm, brain cancer, or issues with the brain’s blood vessels.

TNK has not undergone well-controlled studies to assess its effects during pregnancy. People taking defibrotide or mifepristone also need to avoid tenecteplase.

Tenecteplase (TNK) is a thrombolytic tissue plasminogen activator (tPA) drug that can break down blood clots after an ischemic stroke. It is available as a single dose with a half-life of 20 to 25 minutes.

The Food and Drug Administration (FDA) has not approved TNK as a treatment for ischemic stroke, but several studies and trials have shown it to be as effective as alteplase, another tPA drug. It is also generally lower in cost and does not require ongoing infusion in the same way as alteplase.