Medication Warning Signs: Medicines That May Increase the Risk of Blood Clots and Heart Attacks

Medications play an important role in preventing and treating illness, relieving pain, and improving quality of life. However, some medicines can also cause side effects that require attention, particularly when they affect blood clotting, blood pressure, or cardiovascular health.

You may have seen warnings claiming that certain tablets can cause blood clots, thrombosis, or heart attacks. Although some medications can increase these risks in specific circumstances, it is misleading to suggest that all tablets are dangerous or that everyone taking a particular medication will develop a blood clot.

The actual risk depends on the medication, its dose, how long it is taken, your medical history, and other factors.

Understanding which medications deserve attention, recognizing the warning signs of a blood clot, and knowing when to seek urgent medical care can help you make informed decisions about your health.

1. What Is a Blood Clot?

A blood clot forms when blood changes from a liquid into a thicker mass.

Clotting is a normal and essential process. When you cut yourself, for example, your body forms a clot to help stop the bleeding.

Problems occur when a clot forms inside a blood vessel without an appropriate reason or fails to dissolve when it should.

A clot can restrict blood flow and prevent oxygen from reaching tissues.

There are two major categories of blood clots:

Venous blood clots: These develop in veins. A deep vein thrombosis, or DVT, commonly occurs in the leg. If part of the clot travels to the lungs, it can cause a pulmonary embolism, which is a medical emergency.

Arterial blood clots: These develop in arteries and can block blood flow to vital organs. Depending on their location, they can contribute to a heart attack or ischemic stroke.

Although these conditions involve blood clots, they do not all develop for the same reasons or carry identical risk factors.