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Generic name: alteplase [ AL-te-plase ]
Brand names: Activase, Cathflo Activase
Dosage forms: injectable powder for injection (2 mg), intravenous powder for injection (100 mg; 50 mg)
Drug class: Thrombolytics

Medically reviewed by on Jun 1, 2023. Written by Cerner Multum.

What is alteplase?

Alteplase is a thrombolytic (THROM-bo-LIT-ik) drug, sometimes called a "clot-busting" drug. It helps your body produce a substance that dissolves unwanted blood clots.

Alteplase is used to treat a stroke caused by a blood clot or other obstruction in a blood vessel. Alteplase is also used to prevent death from a heart attack (acute myocardial infarction).

Alteplase is also used to treat a blood clot in the lung (pulmonary embolism).

Alteplase is also used to dissolve blood clots that have formed in or around a catheter placed inside a blood vessel. This improve the flow of medicines injected in through the catheter, or blood drawn out through the catheter.

Alteplase may also be used for purposes not listed in this medication guide.

Alteplase side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Alteplase increases your risk of bleeding, which can be severe or fatal. Call your doctor or seek emergency medical attention if you have bleeding that will not stop. Bleeding may occur from a surgical incision, or from the skin where a needle was inserted during a blood test or while receiving injectable medication. You may also have bleeding on the inside of your body, such as in your stomach or intestines, kidneys or bladder, brain, or within the muscles.

Call your doctor or get emergency medical help if you have signs of bleeding, such as:

Also call your doctor at once if you have:

Bleeding is the most common side effect of alteplase.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Alteplase increases your risk of severe or fatal bleeding, especially from a surgical incision, or from the skin where a needle was inserted. Seek emergency help if you have any bleeding that will not stop.

Before taking this medicine

You should not be treated with alteplase if you are allergic to it, or if you have:

If possible before you receive alteplase, tell your doctor if you have ever had:

In an emergency situation it may not be possible to tell your caregivers if you are pregnant or breast-feeding. Make sure any doctor caring for your pregnancy or your baby knows you have received alteplase.

How is alteplase given?

Alteplase is given as an infusion into a vein. A healthcare provider will give you this injection.

Alteplase is usually given within 3 hours after the first signs of stroke or heart attack symptoms. Your breathing, blood pressure, oxygen levels, and other vital signs will be watched closely.

You will also be watched closely for several hours after receiving alteplase, to make sure you do not have an allergic reaction to the medication.

When used to clear blood clots from a catheter, alteplase is given in 1 or 2 doses.

Your doctor may prescribe a blood thinner or other medication to help prevent future blood clots. Carefully follow all dosing instructions. These medications can make it easier for you to bleed, even from a minor injury.

What happens if I miss a dose?

Because you will receive alteplase in a clinical setting, you are not likely to miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid after receiving alteplase?

Ask your doctor before taking aspirin or ibuprofen (Motrin, Advil) shortly after you have received alteplase. These medications can increase your risk of bleeding.

Avoid activities that may increase your risk of bleeding or injury. Use extra care to prevent bleeding while shaving or brushing your teeth.

What other drugs will affect alteplase?

Tell your doctor about all your other medicines, especially:

This list is not complete. Other drugs may affect alteplase, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Popular FAQ

There is no antidote for Activase; if a patient experiences severe bleeding during Activase therapy, immediately discontinue treatment and provide supportive therapy such as tranexamic acid or aminocaproic acid, or fresh frozen plasma or cryoprecipitate if fibrinogen levels are less than 150mg/dL. Stop all other antiplatelet or anticoagulant treatments and investigate (eg, CT brain, CT abdo/pelvis; FBC, coagulation profile [repeat every 2 hours until bleeding controlled]). Continue reading

How Activase is given or administered depends upon the patient’s weight and what it is being used to treat (such as a stroke, pulmonary embolism, or myocardial infarction. For example, when used to treat a heart attack (myocardial infarction), there are two Activase dose regimens, an accelerated and a 3-hour regimen, with different recommendations depending on if the patient is over 67kg or not. For the accelerated regimen, adults weighing 67 kg or less get a 15 mg IV bolus, followed by 0.75 mg/kg IV (not to exceed 50 mg) infused over 30 minutes, and then 0.5 mg/kg IV (not to exceed 35 mg) over the next 60 minutes Adults greater than or equal to 67 kg get a 15 mg IV bolus, followed by 50 mg IV infused over 30 minutes, and then 35 mg IV infused over the next 60 minutes Continue reading

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.