Table of Contents

I. The Function of Blood Thinners

II. Blood Thinners & NSAIDs

III. Depression Medications & Blood Thinners

IV. Antibiotics & Blood Thinners

V. Be Aware of Vitamin K

VI. FAQ: How Can I Avoid Interactions While Taking a Blood Thinner?

The Function of Blood Thinners 

Blood thinners are medicines that help prevent blood clots from forming and can keep existing clots from getting bigger. They may be prescribed to people with certain heart or blood vessel conditions or those who have a higher risk of developing blood clots. [1] Examples of anticoagulants include Xarelto (rivaroxaban), Coumadin (warfarin), or Eliquis (apixaban). [2]

Blood thinners may be prescribed for conditions or situations such as:

• Atrial fibrillation
• Heart valve replacement
• A higher risk of blood clots after surgery
• Congenital heart defects
• Certain heart or blood vessel diseases [1]

Blood clotting is a normal process that helps stop bleeding after an injury. Platelets, proteins, and other blood cells stick together to form a clot while the body heals. [3] Because anticoagulants reduce the body's ability to form blood clots, they can also increase the risk of bleeding. [4] This is why it is important to take blood thinners as prescribed and tell your healthcare provider about other medicines or supplements you use.

Blood Thinners & NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil) and naproxen (Aleve), are commonly used to relieve pain. NSAIDs can affect how platelets work and interfere with normal blood clotting. Taking an NSAID with a blood thinner can increase the risk of bleeding, including bleeding in the digestive tract. [5]

Talk to your doctor before taking any pain reliever with a blood thinner. If a painkiller is needed, your doctor may recommend using the lowest effective dose for the shortest amount of time. [5] Some common products to ask about include: 

• Advil
• Motrin
• Aleve
• Excedrin
• Bayer
• Alka-Seltzer
• Pepto-Bismol
• Alka-Seltzer Plus [5]

Depression Medications & Blood Thinners

Taking a selective serotonin reuptake inhibitor (SSRI) with an oral anticoagulant may increase the risk of major bleeding. In one study, people taking both an SSRI and an oral anticoagulant had a 33% higher risk of major bleeding compared with those taking an anticoagulant alone. The risk was highest during the first few months of taking both medications. [6]

SSRIs may increase bleeding risk because serotonin helps platelets activate and stick together during blood clotting. SSRIs reduce the amount of serotonin in platelets by up to 80% to 90%. [6] Let your doctor know about all of the medicines you take, including antidepressants and blood thinners, so they can consider possible interactions and adjust your treatment plan if needed. 

Antibiotics & Blood Thinners

Warfarin can interact with some antibiotics and antifungal medications. Examples include cotrimoxazole, cephalexin, penicillin, itraconazole, and ketoconazole. These medications can increase warfarin's blood-thinning effect and raise the risk of internal or prolonged bleeding. [7]

If you take warfarin and need an antibiotic or antifungal medication, let your doctor know about all of the medications you take so they can monitor your treatment and adjust your warfarin dose if needed. Interactions are not limited to pills. Some antibiotic and antifungal ointments, creams, and suppositories may also interact with warfarin. [7]

Be Aware of Vitamin K

Vitamin K can affect how well warfarin works because vitamin K helps your blood clot, while warfarin slows the clotting process. If you take warfarin, try to keep the amount of vitamin K in your diet about the same from day to day. Sudden increases or decreases in vitamin K-rich foods may affect your warfarin dose. [8]

Foods that are high or moderate in vitamin K include kale, spinach, broccoli, Brussels sprouts, and cabbage. Let your doctor know about how much vitamin K you usually eat and try to keep your intake consistent. If you want to make a major change to your diet or start eating more vitamin K-rich foods, talk to your doctor first. [8]

FAQ: How Can I Avoid Interactions While Taking a Blood Thinner?

To avoid interactions while taking a blood thinner, check with your doctor or pharmacist before starting any new medication, supplement, vitamin, or over-the-counter product. Blood thinners help prevent clots from forming or getting larger, but they can also increase bleeding risk. Some products can make that bleeding risk higher, while others can affect how well your blood thinner works.

This is especially important with NSAID pain relievers, certain antidepressants, antibiotics, antifungals, and vitamin K-rich foods if you take warfarin. Let your doctor know about all medications you are taking, as they may need to monitor you more closely, adjust your dose, recommend a safer alternative, or advise you to keep your diet consistent. 

To lower your risk of blood thinner interactions:

1. Tell your doctor and pharmacist about every medication and supplement you take.
2. Ask before using NSAIDs such as Advil, Motrin, or Aleve.
3. Mention antidepressants, especially SSRIs, if you take an oral anticoagulant.
4. Tell your provider if you take warfarin and need an antibiotic or antifungal medication.
5. Keep vitamin K intake consistent if you take warfarin.
6. Do not make major diet changes without checking with your doctor.

The content in this article is intended for informational purposes only. This website does not provide medical advice. In all circumstances, you should always seek the advice of your physician and/or other qualified health professionals(s) for drug, medical condition, or treatment advice. The content provided on this website is not a substitute for professional medical advice, diagnosis, or treatment.