Feeling constantly fatigued can be tough, especially when you’re already living with a serious health condition like pulmonary hypertension (PH). If you have PH, you may be prescribed blood thinners to reduce the risk of blood clots and other related conditions. But could the blood thinners you’re taking be contributing to your exhaustion?

A myPHteam member who was taking blood thinners for PH asked, “Do blood-thinning drugs make your energy level low? They made me so sick and exhausted I couldn’t even get out of bed.

Fatigue goes beyond feeling tired, generating a lack of energy that interferes with your daily life. People with PH can experience fatigue for many reasons. For example, they may get limited exercise and have reduced oxygen levels, problems with sleep, and other health conditions.

What Are Blood Thinners?

Despite the name, blood thinners don’t actually thin your blood. Instead, these medications make it more difficult for your body to form blood clots that might cause a heart attack, stroke, or block blood vessels.

People may take blood thinners if they have an increased risk of blood clots due to medical conditions such as:

• Heart disease
• Blood vessel disease
• Atrial fibrillation (irregular heartbeat)
• Heart valve replacements
• Surgery

Some people with PH do have a higher risk of developing blood clots. The increased pressure in pulmonary arteries caused by PH can put stress on the heart and arteries over time, causing the heart to become weaker. This stress can cause a disturbance in blood flow that increases the risk of blood clots forming. A blood clot in the heart can get lodged in the lungs, causing a pulmonary embolism, which could make PH symptoms worse.

Depending on your diagnosis, you may take blood thinners for a few months, a few years, or for the rest of your life. For example, if you develop a blood clot in your leg, you may be on a blood thinner for three to six months. After a heart attack, you may be on a blood thinner for up to a year. However, people with chronic thromboembolic pulmonary hypertension (CTPH) may need to take anticoagulants for the rest of their lives.

Types of Blood Thinners

There are two main types of blood thinners — anticoagulants and antiplatelets.

Anticoagulants interrupt the body’s process of making clots. The oldest and most common anticoagulant is warfarin (Coumadin). Warfarin works by blocking vitamin K, which is used to make many of the proteins involved in forming blood clots. Although warfarin is very effective at preventing blood clots, it has several food and drug interactions and requires frequent blood tests and dose adjustments.

Direct oral anticoagulants (DOACs) are newer anticoagulants that don’t have as many food and drug interactions as warfarin. They work by blocking thrombin, which is needed for forming blood clots. Examples of DOACs are:

• Rivaroxaban (Xarelto)
• Apixaban (Eliquis)
• Dabigatran (Pradaxa)
• Edoxaban (Savaysa)

Antiplatelet medications prevent the small blood cells called platelets from sticking together to form a clot. Examples of antiplatelet medications include:

• Aspirin
• Clopidogrel (Plavix)
• Prasugrel (Effient)
• Ticagrelor (Brilinta)

Side Effects of Blood Thinners

Fatigue is not usually listed as a common side effect of blood thinners. The side effects depend on the specific blood thinner you are taking. Some possible side effects include:

• Nose bleeds
• Bleeding gums
• Bruising
• Upset stomach
• Nausea
• Diarrhea
• Decreased appetite
• Hair loss

Blood thinners make it take longer for your blood to clot. This process can increase your risk of internal bleeding, which could be life-threatening in some cases. It is important to be aware of serious symptoms of internal bleeding, such as:

• Blood in your urine
• Black, tarry stool
• Red blood in your stool
• Vomit that looks like coffee groups
• Nosebleeds that don’t stop
• Difficulty breathing
• Heavy bleeding during a period
• Any bleeding that won’t stop

Can Blood Thinners Cause Fatigue?

If you have noticed fatigue and increased tiredness while taking a blood thinner, you aren’t alone. Both doctors and people taking blood thinners have also reported fatigue as a side effect of blood thinners. Scientists have therefore conducted several medical studies to find out why it may be happening.

A 2005 study found that short-term use of warfarin was not associated with fatigue. Another study from the Archives of Internal Medicine found that people who took warfarin over the long term did not generally notice a decrease in their overall health.

The results of a 2020 study suggest that people taking rivaroxaban to treat deep vein thrombosis (a blood clot in a vein) do not experience increased fatigue.

A 2021 study found that clopidogrel can cause severe fatigue in some people. However, this side effect is very rare and only occurs in people who are more sensitive to clopidogrel.

Excessive bleeding caused by blood thinners could make you feel fatigued by causing iron-deficiency anemia. People with iron-deficiency anemia may feel tired, weak, or fatigued because their blood can’t carry enough oxygen around the body.

Other Causes of Fatigue in People Living With PH

Fatigue caused by blood thinners could add to PH-related fatigue. Almost 60 percent of people living with PH experience fatigue. Some researchers believe decreased oxygen is the main cause of fatigue in PH. PH can make it harder for your heart and lungs to deliver oxygen to your brain and the tissues around your body, leading to mental and physical fatigue.

Other causes of fatigue in PH include:

• Inflammation — Increased pressure in the pulmonary arteries can cause inflammation, which may lead to symptoms of fatigue.
• Lack of physical activity — Feeling fatigued can make engaging in physical activity and exercising more difficult. Without exercise, you may tire more easily.
• Sleep problems — PH is also associated with sleep problems such as insomnia and obstructive sleep apnea. A lack of restful sleep can also contribute to fatigue in people with PH.
• Medications — The side effects of PH treatments may cause fatigue. For example, phosphodiesterase-5 (PDE-5) inhibitors are associated with physical fatigue and feelings of reduced motivation.
• Associated conditions — Heart problems, other lung conditions, lupus, and liver disease can also contribute to fatigue in PH.

What Should You Do if You Experience Fatigue While Taking a Blood Thinner for PH?

Talk to your doctor if you experience fatigue that doesn’t get better. Your doctor can help you uncover the cause of your fatigue and help you find ways to improve it. The best way to fight fatigue is to treat the underlying cause. Your doctor may make changes to your treatment plan and suggest lifestyle changes to control your PH symptoms.

Living with fatigue can be hard. The following tips may help:

• Eat a balanced diet and drink plenty of water.
• Get physical activity when you can, under the advice of your doctor.
• Keep a fatigue diary to help you keep track of when you feel the most fatigued.
• Try meditation.
• Ask for help when you need it.

Although blood thinners are an essential medication for many people with PH, they can cause fatigue as a side effect. Speak with your doctor if you experience any symptoms of fatigue or other adverse reactions while taking blood thinners. They may need to adjust your medication dosage or switch to a different type of blood thinner. By working closely with your health care team, you can manage your condition and reduce side effects like fatigue.

Talk With Others Who Understand

On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 50,000 members come together to ask questions, give advice, and share their stories with others who understand life with PH.

Have you experienced fatigue while taking a blood thinner? Share your story in the comments below, or start a conversation by posting on your Activities page.