Thrombolysis (Thrombolytic Therapy): What to Know

Written by Felicia Wilson
Medically Reviewed by Zilpah Sheikh, MD on October 01, 2025
6 min read

Thrombolysis, also known as thrombolytic therapy, is a treatment to dissolve dangerous clots in blood vessels, improve blood flow, and prevent damage to your tissues and organs. If you have a heart attack, ischemic stroke, or a pulmonary embolism, your doctor may use this treatment.

There are three ways thrombolytic therapy can be given:

  • Through an IV (called systemic thrombolysis)
  • Through a catheter guided directly to the site of the clot (called catheter-directed thrombolysis)
  • Through surgery to remove the clot (thrombectomy)

Systemic thrombolysis is usually reserved for immediate life-threatening conditions such as a heart attack, stroke, or pulmonary embolism.

If you get catheter-directed thrombolysis, it’s usually done in a catheterization lab or radiation suite. A team of doctors and nurses will direct a catheter with medications directly to the clot. Here’s what to expect:

  • You’ll be given medication to relax you, and the treatment area will be numbed.
  • A vascular surgeon will insert the catheter into a vein, usually in your groin, neck, or behind the knee.
  • Medicine is delivered through the tube into the clot.
  • If necessary, a small machine is inserted through the catheter to break up the clot.
  • If the surgeon finds other narrow areas in the vein, they may perform angioplasty — a treatment to widen the vein after the blood clot is dissolved. This involves inserting a small device with an inflatable balloon into the narrowed section of the vein. The balloon is then inflated and deflated several times before it’s removed. If there is severe narrowing, the surgeon may insert a permanent stent — a small mesh tube — instead.
  • The catheter is removed, and the puncture is closed.
  • Your blood pressure will be checked every 15 minutes after the procedure for at least two hours, then half-hourly for six hours, and hourly for the next 16 hours. This is essential to prevent complications.

You could also have surgery, also called thrombectomy, to remove a blood clot. You would usually need this surgery if your blood clot can’t be treated by clot-busting drugs, anticoagulants, or blood thinners.

You may be given thrombolytic drugs to:

  • Prevent the ongoing damage of heart attacks
  • Halt ongoing damage from ischemic stroke
  • Break up blood clots in other blood vessels in the body, such as deep vein thrombosis (DVT), pulmonary embolism, or leg artery blockage

It’s important to know the signs and symptoms of a stroke and a heart attack. Call for emergency help (911 in most areas) right away if you or someone you know is having them. The faster treatment is given, the quicker blood flow will be restored to the area and the greater the chance to prevent long-term damage, or even death.

There are several drugs to break up clots, including:

  • Alteplase
  • Reteplase
  • Streptokinase
  • Tenecteplase
  • Tissue plasminogen activator (tPA)
  • Urokinase

Thrombolytic therapy is probably not right for you if you have or have had any of the following:

  • A recent head injury
  • A recent stroke
  • Bleeding problems
  • Active peptic ulcers
  • Pregnancy
  • Recent surgery
  • History of blood-thinning medicines such as warfarin (Coumadin)
  • Uncontrolled, severe high blood pressure (anything above 180/110)
  • Dementia
  • Severe liver disease

Certain drugs may raise your risk of bleeding if you are prescribed clot busters. Tell your doctor the names of all medications, over-the-counter drugs, herbal medications, supplements, or vitamins you are taking. Examples of these include:

Also, tell your doctor if you’ve been given any clot busters in the past six months. Some thrombolytic medications cannot be given a second time within that period.

Thrombolysis is very effective in breaking up blood clots that can lead to heart attacks and strokes. This treatment is most effective if used immediately. Ideally, you should receive thrombolytic medicines within the first 30 minutes after arriving at the hospital for a heart attack. For ischemic stroke, thrombolytic meds should be used within the first three hours. 

If you have deep vein thrombosis (DVT), anticoagulants are the standard treatment. These are medications that also thin the blood to stop further clots from forming. They are effective in helping prevent a blood clot from traveling to the lungs (pulmonary embolism), but they may not thoroughly dissolve the blood clot. That puts you at greater risk of developing post-thrombotic syndrome (PTS).

You can get thrombolytic therapy for DVT if you meet the following criteria:

  • You have an iliofemoral DVT, which means it’s in a thigh vein. This type of DVT is more likely to advance to a pulmonary embolism.
  • You have severe DVT causing swelling or a limb- or life-threatening proximal clot.
  • Your DVT is in the upper half of your body.
  • You have had symptoms for less than 14 days.
  • You’re in good health.

If catheter-directed thrombolytic therapy is not available at your hospital, your doctor may decide to do systemic thrombolytic therapy if you meet all of the above criteria.

As with any drug, there can be side effects with clot busters. Notify your doctor if you notice:

If you have any questions about thrombolytic medications, ask your doctor.

Thrombolysis, also called thrombolytic therapy, is used to quickly dissolve blood clots in life-threatening conditions, such as heart attacks, strokes, or pulmonary embolisms. You can get it either through an IV or a catheter.

Thrombolytic therapy works best if you get it quickly. Ideally, you should get it within 30 minutes for heart attacks and within three hours for strokes. 

Not everyone can get this therapy. Recent surgeries, bleeding disorders, or high blood pressure may make this treatment too risky for you.

Does thrombolysis hurt?

Generally, the procedure does not hurt. You’ll be given anesthesia, so you won’t feel any pain during the procedure. After thrombolytic therapy, you may have bruising, bleeding, or swelling. This happens where the tube has entered your body in 1%-3% of cases. This used to happen more frequently until doctors became stricter about which patients got thrombolytic therapy. You may also experience bleeding elsewhere, such as your intestines or brain, but it’s extremely rare.

How long does thrombolysis take?

The procedure can take anywhere from 1 to 48 hours, depending on where the blood clot is. For example, if you have DVT, an IV can take up to 48 hours. Thrombolytic therapy can also be given via a catheter. 

What are the risks of thrombolysis injections?

You may have bruising, bleeding, or swelling with thrombolytic therapy. This happens where the tube has entered your body in 1%-3% of cases. This used to happen more frequently until doctors became stricter about who got thrombolytic therapy. You may also experience bleeding elsewhere, like your intestines or brain, but it’s extremely rare.

What is the failure rate of thrombolysis?

The failure rate of thrombolysis ranges from 9% to 25% and higher, depending on the type of thrombolytic med used, when it was given, and for what condition. Other factors that could keep the drugs from working include your age and whether you have other underlying conditions such as high blood pressure, diabetes, or chronic kidney disease.