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Preventing Blood Clots After Being in the Hospital: The Role of New Blood Thinners

Preventing Blood Clots After Being in the Hospital: The Role of New Blood Thinners

This article is for people who were recently in the hospital and may be at risk for a blood clot or for anyone who wants to learn more about preventing blood clots. The goal of this patient education activity is for you to learn about treatment options, including new blood thinners, and to prevent blood clots after being discharged from the hospital.

You will learn:

  • Why you may be at risk for a blood clot after being in the hospital

  • How to know if you have a blood clot

  • Treatments for blood clots, including blood thinners

  • The side effects of blood thinners

  • How to lower your risk for blood clots at home

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You May Be at Risk for a Blood Clot After Being in Hospital

If you were in the hospital recently, you may be at risk for getting a blood clot in your blood vessels (called thrombosis). Blood clots can happen up to 3 months after being in the hospital.

Having a blood clot is serious because it can slow or block blood flow and oxygen supply to your legs or organs.

The good news is, blood clots are preventable. It is important for you to know your risk, know the warning signs, and know what the treatment options are for a blood clot.

Reference: World Thrombosis Day Website

Are You at Risk for a Blood Clot?

Blood clots can happen in men and women of all ages, but having these risk factors while you were in the hospital increases your chance of developing a blood clot after you are discharged from the hospital:

  • Age 60 years or older

  • Had a previous blood clot

  • Stayed in the intensive or coronary care unit (ICU or CCU)

  • Could not move on your own for 7 days or more in a hospital bed

  • Cancer or received chemotherapy

  • Paralyzed below the waist

  • Blood disorder that makes you have blood clots

  • Major surgery (hip, knee, heart)

Types of Blood Clots

The 2 major types of blood clots are:

  • Deep vein thrombosis (DVT): a blood clot that develops in your legs

  • Pulmonary embolism (PE): a blood clot that develops in your lungs, or a DVT clot that travels to your lungs through your blood vessels. Sometimes, a blood clot in your lungs can lead to death

To find out your risk for getting a DVT or PE, a doctor or nurse will ask you some questions, such as your age, medical history, medicines you are taking, and your lifestyle. This risk assessment should happen while you are in the hospital and again before you go home. Based on your risk, you may need medicine to prevent a blood clot.

How Will I Know if I Have a Blood Clot?

DVT and PE are serious, life-threatening conditions. Get medical help immediately if you have these symptoms:

Deep Vein Thrombosis (DVT)

Pulmonary Embolism (PE)

Pain, throbbing, cramping or tenderness in your leg, usually in the calf

Swelling, including ankle or foot

Redness or discoloration


Unexplained shortness of breath

Fast breathing

Sharp chest pain (may hurt more when you take a deep breath)

Fast heart rate

Light headedness or passing out

Coughing up blood

To confirm that you have a blood clot, your doctor may perform some tests:

  • Blood tests

  • Ultrasound of your leg for a DVT

  • Computed tomography (CT) scan of your chest for a PE

Preventing and Treating Blood Clots While You Are in the Hospital

Depending on your risk, the size of the blood clot, and where it's located in your body, there are different ways to treat it. For example, patients with a high risk of having a blood clot may receive a blood thinner called heparin through the vein (IV) while they are in the hospital, and then go home on a blood thinner.

In the hospital:

  • Compression devices squeeze the legs to improve blood flow

  • Clot-busting medicines dissolve blood clots

  • Surgery removes blood clots

  • Blood thinners given by IV or injection that prevent blood clots

After discharge from the hospital:

  • Blood thinners taken as pills that treat clots and prevent new ones from forming

Prevention of Blood Clots in the Hospital: Compression Devices

Compression devices are used to improve blood flow between your legs and your heart. Keeping blood moving in your veins and arteries helps prevent blood clots from forming.

  • In the hospital, there is a device with cuffs that are placed around your legs and filled with air. They squeeze your legs (just like a blood pressure cuff), deflate, and start over again

  • At home, you can wear compression stockings to help with blood flow and swelling. The stockings can be worn (either on both legs or just 1) during the day and taken off before bed. You can find compression stockings at your local pharmacy

  • If you are traveling on an airplane for 4 or more hours, it is a good idea to wear compression stockings during your flight.

Treatment of Blood Clots in the Hospital: Clot-Busting Therapy

Clot-busting medicine, which dissolves clots and improves blood flow quickly in the affected blood vessel, is given in the hospital. Your doctor may recommend it if you have symptoms of a DVT, are at high risk for a PE, have a clot above your knee, or have a large clot, and want to decrease problems after treating the blood clot.

Clot-Busting Medicines

Alteplase (Activase®)*

Streptokinase (Streptase®)

Urokinase (Kinlytic®)*

*For PE, not DVT.

After treatment with a clot-busting medicine, you can still be at risk for future clots, which is why your doctor may recommend you also take a blood thinner.

Treatment of Blood Clots in the Hospital: Surgery

If you have a very large clot, your doctor may advise you to get it surgically removed in the hospital.

After surgery, you can still be at risk for future clots, which is why your doctor may recommend that you take a blood thinner.

Prevention of Blood Clots in the Hospital: Injectable Blood Thinners

Blood thinners (also known as anticoagulants) can treat and/or prevent new blood clots from forming. One of the oldest kinds of blood thinners is called heparin. Heparin can be given by IV or by injection in the hospital to prevent blood clots. It requires close monitoring so your doctor can adjust the dose.

Another type of heparin comes as injections, which you can give to yourself every day for 7-10 days or longer to treat blood clots at home.

Injectable Blood Thinners

Dalteparin (Fragmin®)

Enoxaparin (Lovenox®)

Fondaparinux (Arixtra®)


Tinzaparin (Innohep®)

Some people experience mild irritation, pain, bruising, redness, and swelling at the injection site.

Prevention of Blood Clots During and After Discharge From the Hospital: Pill Blood Thinners

There are also blood thinners that are pills. In the past, warfarin was commonly used to treat and prevent DVT and PE. It is still used in some patients, but there are some side effects, so patients need to have regular blood tests.

The direct anticoagulants (DOACs) are the newest type of blood thinners. DOACs slow down your body's process of making blood clots and prevent clots from forming.

  • DOACs do not require regular blood tests, but there is a risk of major bleeding and an increased risk of future clots if you stop taking them or do not take them as prescribed

  • A DOAC might be right for you if you have a high risk for a blood clot and a low risk of bleeding

  • You may start a DOAC while you are in the hospital and then continue taking it after you are discharged. Your doctor will decide how long you will need to take the DOAC

Blood Thinners That Come as Pills

Betrixaban (Bevyxxa®)*

Rivaroxaban (Xarelto®)*

Warfarin (Coumadin®)

*DOAC approved for preventing blood clots after discharge from the hospital.

A blood clot is made up of plaque (cholesterol build up), platelets, and red blood cells.

Side Effects of Blood Thinners

People taking blood thinners can have serious side effects. Call your doctor if you have any of these problems:

  • Unusual pain, swelling, or discomfort

  • Unusual bruising

  • Bleeding for a long time from cuts, the gums, shaving nicks

  • Nosebleeds that don't stop

  • Coughing up blood

  • Blood in vomit or urine

  • Blood in stools or dark, tarry stools

  • Severe headache, dizziness/fainting, feeling tired

  • Trouble swallowing

Tips to Prevent Blood Clots After Leaving the Hospital

  • Move around, do not sit or stand in one place for more than 1 hour

  • While you are sitting, flex your calves, ankles, and thighs from time to time to keep blood flowing

  • While sitting or lying down, try raising your feet about6 inches above your heart

  • Be physically active for at least 20 minutes, 3 to 4 times a week

  • Stay hydrated, drink 64 ounces of water a day

  • Do not smoke

  • Limit alcohol intake

  • Wear compression stockings, especially for flights that are 4 hours or more

Questions to Ask Your Doctor

  • Am I at risk for a blood clot after leaving the hospital?

  • What should I do to prevent blood clots?

  • What signs and symptoms should I look for?

  • When should I get emergency help?

  • Which blood thinner is right for me?

Test Your Knowledge

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You have successfully completed the program: Preventing Blood Clots After Being in the Hospital: The Role of New Blood Thinners

View Additional Materials View Additional Materials on this topic that you may find useful

Centers for Disease Control and Prevention: Understanding Blood Clots

World Thrombosis Day: Patients' Rights

World Thrombosis Day: What to Know Before Going to the Hospital

World Thrombosis Day: Personal Stories

Authors and Disclosures

Clinician Reviewer

Susan L. Smith, MN, PhD

Senior Scientific Director, Medscape, LLC

Disclosure: Susan L. Smith, MN, PhD, has disclosed no relevant financial relationships.


Asha P. Gupta, PharmD, RPh

Scientific Content Manager, Medscape, LLC

Disclosure: Asha P. Gupta, PharmD, RPh has disclosed no relevant financial relationships.

Peer Reviewer

Amy Hess Fischl, MS, RDN, LDN, BC-ADM, CDE

University of Chicago Medicine

Disclosure: Amy Hess Fischl, MS, RDN, LDN, BC-ADM, CDE has disclosed the following relevant financial relationships: Served as an advisor or consultant for: Xeris Pharmaceuticals, Inc. Served as a speaker or a member of a speakers bureau for: Abbott Diabetes Care; Xeris Pharmaceuticals, Inc.


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