Bleeding and Other Complications of Blood Thinners

Stroke prevention is a vital part of taking care of your health. If you have stroke risk factors, taking the right steps to reverse those risk factors can effectively reduce your risk of stroke and disability. 

Blood thinners are one of the types of medications that have been proven to reduce stroke risk for people with some stroke risk factors, including atrial fibrillation. If you want to know more about the different kinds of blood thinners used in stroke prevention, you can find out more here.


Blood thinners are necessary for many people, but they can cause some complications. Here are the common side effects of blood thinners. 


If you take a blood thinner, you might notice a bruise underneath your skin after what felt like a minor bump or even when you don’t remember any bumps at all. Your body bleeds easily when you take blood thinners, and this can allow the tears in your blood vessels caused by minor injuries to cause bruises. 

What to do- do not wrap or massage the area, because that can make the bleeding worse. Do not apply a heat pad, because they can prevent the bleeding from quickly improving. A cold pack might help a little bit, so if it gives you pain relief, a cold pack is fine. See a medical professional if the bruise is large, if it continues to grow underneath the skin or if the area becomes swollen. 

Bleeding in the eye

Blood in the white part of your eye is called a conjunctival hemorrhage, and you can get it after coughing or sneezing if you take a blood thinner.

What to do- do not rub your eye or apply heat to your eye. If you experience pain, any changes in your vision or if the red spot gets larger, see a medical professional. 

Stomach or intestinal bleeding

This is called gastrointestinal bleeding. Usually, it doesn't cause pain. If you notice a deep black color in the toilet or if you notice red blood in the toilet, those are the signs that you may have bleeding of the stomach or intestines.


What to do- you should definitely make an appointment to see your doctor if you have signs of gastrointestinal bleeding. If you experience sudden bleeding or if you see large amounts of blood, black stool or bloody diarrhea, then you need to get an urgent medical attention. 

Coughing up blood 

Coughing or spitting up blood is never normal. It can come from your throat, your lungs, or your esophagus. Most of the time, it is not painful and it may only happen off and on. 

What to do- you should definitely let your doctor know that you are coughing up blood. 


Bleeding from small cuts can last much longer than usual if you are taking a blood thinner. Most of the time, if you press down on the area of bleeding, the blood flow will stop- but it may take 5-10 minutes instead of the usual 1-3 minutes. Sometimes, a cold pack or an ice pack can help slow down the bleeding. 

What to do- when you are taking blood thinners, it takes a while longer than usual for a bleeding wound to stop. However, it is worth mentioning to your doctor, as sometimes you might need a slight dose adjustment of your blood thinner. 

Slow wound healing  

This is typical and expected if you are taking a blood thinner.

A wound or a bruise may take longer to heal than usual. 

What to do-as with the bleeding mentioned above, this problem is anticipated when you are taking a blood thinner. If you have a large wound, it is important to cover it to make sure that it doesn't become infected during the slow healing process. 

Bleeding in the brain

This is an uncommon problem with blood thinners. However, if you are taking a blood thinner, you are slightly more prone to bleeding in the brain and more prone to brain injuries after head trauma. The signs of bleeding in the brain include headaches, vision changes, weakness, slurred speech, numbness and dizziness.

If you have a brain aneurysm, the decision to take a blood thinner for stroke prevention is a very complex one. Find out about brain aneurysm prognosis here.

What to do- if you experience any of the symptoms of bleeding of the brain, it is important to get emergency medical attention right away.


If you need to take a blood thinner, you should familiarize yourself with the common side effects so that you can recognize them if you experience any of them.



New oral anticoagulants: their advantages and disadvantages compared with vitamin K antagonists in the prevention and treatment of patients with thromboembolic events, Mekaj YH, Mekaj AY, Duci SB, Miftari EI, Therapeutics and Clinical Risk Management, June 2015


Diagnosis and management of common acquired bleeding disorders, De Simone N, Sarode R., Seminars in Thrombosis and Hemostasis, March 2013

Continue Reading