5 Medications That Can Cause Blood Clots—and What to Watch Out For

Certain medications, while necessary for treating serious conditions, may come with a hidden risk: blood clots. Whether you’re managing pain, hormones, or chronic disease, it’s critical to understand the connection between your prescriptions and clotting risks.

Here’s what you need to know about which medications are linked to blood clots, what symptoms to look for, and when it’s time to seek medical help.

Why Blood Clots Are a Concern

Blood clots can develop when your blood thickens and forms a blockage, usually in the legs (deep vein thrombosis, or DVT), lungs (pulmonary embolism), or brain. Left untreated, clots can be life-threatening. While some people are genetically prone to clotting disorders, others may face increased risk because of medications that affect circulation, hormones, or inflammation.

5 Common Medications That May Increase Blood Clot Risk

Hormonal Birth Control Pills
Combination contraceptives containing estrogen and progestin are known to raise the risk of clotting—especially in smokers or women over 35.
Hormone Replacement Therapy (HRT)
Used to ease menopausal symptoms, HRT can also increase the risk of DVT and pulmonary embolism, particularly in pill form.
Cancer Medications (e.g., Tamoxifen)
Tamoxifen, used for breast cancer, and other chemotherapy drugs can disrupt clotting factors in the blood, heightening the chance of a clot.
Antipsychotics (e.g., Olanzapine, Risperidone)
These medications may increase clot risk by causing weight gain, reduced mobility, and changes in platelet activity.
Steroids (Corticosteroids)
Prednisone and similar drugs used to treat inflammation and autoimmune conditions may affect blood vessel integrity and coagulation.

Signs and Symptoms of a Blood Clot

If you’re taking one of the medications above, watch closely for the following warning signs:

Swelling or pain in one leg (especially the calf)
Warmth or redness around the swollen area
Sudden shortness of breath
Chest pain or tightness
Rapid heart rate or coughing up blood
Sudden confusion or vision changes (may indicate a stroke-related clot)

These symptoms should never be ignored. Seek immediate medical attention if any of these appear, especially if you’ve recently started a new medication or have other risk factors like recent surgery, immobility, or a family history of clotting disorders.

When to Talk to Your Doctor

If you’ve been prescribed a medication associated with clotting risk, it’s important to have an open conversation with your doctor. Ask whether safer alternatives exist or if preventive measures, such as low-dose aspirin or increased activity, could help. Your provider may evaluate your individual risk factors—including family history, age, weight, and mobility—to determine if additional steps should be taken. Staying hydrated, moving frequently, and scheduling regular checkups can also support circulation and early detection. You don’t need to panic—but staying proactive can prevent problems before they start.

Final Thoughts

Understanding how certain medications may increase your risk of blood clots can help you stay ahead of serious complications. If you're starting a new treatment—especially for hormones, cancer, or mental health—monitor your body closely and speak up about any unusual symptoms.

With the right knowledge and timely medical care, blood clots are preventable and treatable. Don’t wait—know the signs, assess your risks, and protect your health one conversation at a time.

Sources

Mayo Clinic – https://www.mayoclinic.org

CDC – https://www.cdc.gov/ncbddd/dvt/index.html

WebMD – https://www.webmd.com/dvt/default.htm

Cleveland Clinic – https://my.clevelandclinic.org

FDA – https://www.fda.gov