COVID-19 and Blood Thinners: What You Need to Know About Risks and Safety

When you have COVID-19, a viral infection that can trigger abnormal blood clotting and inflammation. Also known as SARS-CoV-2 infection, it doesn’t just affect your lungs—it can turn your blood into a sticky, dangerous mix that forms clots in veins and arteries. This is why many hospitalized patients get blood thinners, medications that reduce the blood’s ability to form clots. Also known as anticoagulants, they’re used to prevent deadly clots in the lungs, heart, or brain. But here’s the catch: using these drugs isn’t simple. Too little, and you risk a clot. Too much, and you could bleed internally—sometimes without warning.

Studies show that severe COVID-19 increases clotting risk by up to 30%, especially in older adults or those with existing heart disease or diabetes. Doctors often prescribe low-dose heparin, a common injectable anticoagulant used in hospitals or warfarin, an oral blood thinner that requires regular blood tests to keep things balanced. But if you’re already on blood thinners for atrial fibrillation, deep vein thrombosis, or a past stroke, adding more can push you into dangerous territory. The same goes for mixing them with NSAIDs like ibuprofen or even some herbal supplements—these can spike your bleeding risk.

It’s not just about the drugs. COVID-19 can mess with your platelets and clotting factors in ways we’re still learning. Some people develop tiny clots in their fingers or toes—called "COVID toes"—while others face life-threatening pulmonary embolisms. That’s why monitoring symptoms matters: sudden shortness of breath, chest pain, or unexplained bruising could mean your blood thinners need adjusting. And if you’re not in the hospital, don’t assume you’re safe. Even mild cases can trigger clotting issues, especially if you’re inactive for long periods.

What you’ll find below are real, practical insights from people who’ve walked this path—patients, pharmacists, and doctors sharing what works, what doesn’t, and what to watch out for. From how to talk to your pharmacist about interactions, to why some blood thinners are safer than others during infection, to what signs you should never ignore—these posts give you the tools to stay safe without guesswork.