Thrombolytics

What are thrombolytics?

Thrombolytics are medicines that break up or dissolve blood clots. When blood clots form inside a blood vessel, they can block blood flow and cause a heart attack or stroke. Clots can form in arteries or in veins.

• A clot in a vein is called deep vein thrombosis and can be very dangerous. If part of the clot breaks off and gets to the heart or lungs, it can block blood flow.
• A clot in an artery can stop oxygen from getting to muscle. Lack of oxygen can cause a heart attack or a stroke.

Thrombolytics are sometimes called clot busters. Some common thrombolytics are alteplase (Activase), reteplase (Retavase), tenecteplase (TNKase), streptokinase (Streptase), and urokinase (Abbokinase).

How do they work?

Blood clots are made of a substance called fibrin. Fibrin causes blood to become solid. Thrombolytic medicines work by getting rid of the fibrin. These medicines take a chemical already in your body (plasmin) and change it so that it breaks down the fibrin and gets rid of the clot. These medicines work fast, which is important in getting the blood flowing again.

When are they used?

Thrombolytic medicines are used to break up blood clots and bring back normal blood flow through a blood vessel. Thrombolytics may be used when:

• You have a heart attack. A thrombolytic may be one of the first medicines given after a heart attack. If the blood clot in the heart artery can be removed quickly, the heart muscle gets the oxygen it needs and there is less damage to the heart.
• You have a type of a stroke called ischemic stroke.
• You have a large blood clot in your lungs (called a pulmonary embolism).

Starting this medicine as soon as possible after you feel symptoms of a heart attack or stroke improves your chances of recovery. If you are receiving this medicine because you had a stroke, it must be given within a few hours after having the stroke.

Your healthcare provider will inject this medicine into your bloodstream, usually through a vein in your arm. How it is given to you depends on which thrombolytic medicine you are being given. You may need 1 shot or you may have an infusion into your vein over an hour or so. (An infusion is a slow drip into a large vein.) You may also be given another medicine called heparin, which is a blood thinner that helps prevent your blood from forming another clot.

Your healthcare provider will work very quickly to determine if you should be given this medicine. It is not safe to give thrombolytic medicines to some people. You will be asked several questions about your medical history and current health. You will also have an exam and many tests. To be as safe as possible, thrombolytic medicines will not be used if:

• You already bleed more than normal.
• You have a serious injury or recent surgery that could cause bleeding.
• You are recovering from a stroke.
• You have uncontrolled high blood pressure.

What should I watch out for?

Fibrin is important to help your blood clot when you cut yourself. Because thrombolytic medicines work against fibrin, the medicine can keep your blood from clotting anywhere in your body. So, if bleeding starts from a cut, a scratch, or a nosebleed, it may be hard to stop. A little bit of bleeding may become a big problem. Although rare, this medicine may cause bleeding into the brain. Whenever you are given thrombolytic medicines, you will have regular blood tests to be sure that the risk of bleeding is as low as it can be.

To help prevent serious bleeding, carefully follow the instructions given by your healthcare provider. Watch for signs of bleeding around your injection site and check for blood in your urine or stools. Tell your provider right away if you notice any bleeding.

Many other medicines may affect the action of these medicines. Tell your healthcare provider and pharmacist about any other prescription or nonprescription medicines, vitamins, or natural remedies you are taking.

When should I call my healthcare provider?

Although you will be receiving this medicine in the hospital and will be closely watched for signs of bleeding, contact your healthcare provider right away if you have:

• blood in your urine
• black or tarry stools
• unusual bleeding or bruising
• an irregular heartbeat
• trouble breathing
• severe headache
• chest pain.

Written by Donald L. Warkentin, MD for RelayHealth.
Published by RelayHealth.
© 2009 RelayHealth and/or its affiliates. All Rights Reserved.