One of the side effects of aspirin is reduced platelet function. Aspirin can potentially make issues with blood clotting worse.

Thrombocytopenia is the medical term for low platelet count. Platelets are a type of blood cell that helps your blood clot.

Having a low platelet count can increase your risk of excessive bleeding. Mild thrombocytopenia might not cause noticeable symptoms, but severe thrombocytopenia can lead to life threatening bleeding even from minor injuries.

Aspirin, or acetylsalicylic acid, is an over-the-counter drug commonly used to reduce pain or fever and to reduce heart disease and stroke risk. It falls into a class of drugs known as nonsteroidal anti-inflammatory drugs (NSAIDs).

One of the side effects of aspirin is reduced platelet function. Doctors generally don’t recommend aspirin to people with an already low platelet count since it can potentially exacerbate issues with blood clotting.

Very rare cases of aspirin allergy-induced thrombocytopenia have been reported as well.

Read on to learn more about the connection between aspirin and thrombocytopenia.

Thrombocytopenia can range from mild to severe. A normal platelet count in adults is considered between 150,000 to 450,000 platelets per microliter of blood.

Thrombocytopenia is defined as having less than 150,000 platelets per microliter. Lower platelet counts are associated with more severe bleeding.

Aspirin generally isn’t recommended for people with under 100,000 platelets per microliter since it can reduce the ability of the platelets to stick together.

How aspirin blocks platelet function

Aspirin reduces the ability of your platelets to stick together to form a clot by blocking the activity of an enzyme called cyclooxygenase-1 and reducing the synthesis of a molecule called thromboxane A2.

Blocking the formation of thromboxane A2 prevents exposed platelets from becoming activated over their lifetime. Platelets have a life span of about 7 to 10 days.

How aspirin may affect people with thrombocytopenia

People with thrombocytopenia already have a lower than typical number of platelets, and losing the function of remaining platelets may worsen issues with blood clotting and contribute to the following symptoms and signs:

Severe thrombocytopenia can cause bleeding that can be life threatening.

Doctors often recommend daily low dose aspirin therapy for people at risk of heart disease or who have had a heart attack or stroke to reduce the risk of a future heart attack or stroke. Generally, doctors recommend 81 milligrams of aspirin once per day.

Your doctor may still recommend aspirin for reducing your chance of heart disease if you’re at an elevated risk of heart disease and your thrombocytopenia is mild.

Aspirin in people with cancer and at risk of cardiovascular disease

Thrombocytopenia is common among people with cancer, especially people with blood cancer. As many as 5% to 33% of people with blood cancers have thrombocytopenia.

However, cancer and some cancer treatments can also cause the platelets to stick together and increase the risk of cardiovascular disease.

In a 2017 study, researchers found evidence that aspirin therapy was associated with better survival after a heart attack in people with blood cancer and severe thrombocytopenia.

Researchers hypothesize that platelets may promote the development of certain types of cancer. They’re continuing to investigate whether low dose aspirin therapy may help prevent the progression of cancer by reducing platelet counts.

As of now, aspirin isn’t a regular part of cancer therapy, but it may play a role in cancer therapy in the future.

Thrombocytopenia with a platelet count under 100,000 platelets per microliter is usually considered a contraindication for daily aspirin therapy. A contraindication is a condition that prevents people from being eligible for a certain treatment.

Your doctor can best advise you on whether to stop taking aspirin based on the results of blood tests.

Aspirin usually doesn’t cause thrombocytopenia. Aspirin reduces the ability of the platelets to stick together, but it doesn’t reduce the number of platelets.

Aspirin-induced thrombocytopenia has been reported in very rare cases due to allergic reactions. For example, in a 2021 study, researchers reported a 47-year-old male with thrombocytopenia that was thought to be linked to an allergy to aspirin.

It’s important to speak with your doctor before taking aspirin if you’ve previously been diagnosed with thrombocytopenia or if you have a condition that increases your risk of thrombocytopenia, such as:

Be sure to speak with your doctor before you stop taking aspirin, especially if they recommended taking aspirin to reduce your risk of cardiovascular disease.

Here are some frequently asked questions people have about aspirin and thrombocytopenia.

Does aspirin increase platelet counts?

No. Aspirin reduces the ability of your platelets to stick together. Because of this, doctors typically recommend aspirin to people at risk of heart disease.

Does aspirin interfere with platelet production?

Aspirin interferes with the ability of platelets to stick together and form a clot, but it doesn’t affect the production of platelets. In rare cases, an allergy to aspirin has been linked to a reduced platelet count.

What other drugs can cause thrombocytopenia?

Drug-induced thrombocytopenia can be caused by medications like heparin, ceftriaxone, and some monoclonal antibodies.

Thrombocytopenia is when your body doesn’t produce enough platelets. Aspirin may exacerbate symptoms of thrombocytopenia by impairing the ability of your platelets to stick together. Very rarely, aspirin may induce thrombocytopenia by causing an allergic reaction.

It’s important to speak with your doctor before starting daily aspirin therapy regardless of whether you have thrombocytopenia.