Aromatase Inhibitors – What You Need to Know

If you or someone you know is on an aromatase inhibitor, you probably have questions about how the drug works and whether it could cause bleeding problems. These medicines are mainly used to treat hormone‑positive breast cancer by lowering estrogen levels in the body. Lower estrogen can slow tumor growth, but it also changes how blood clotting works. Understanding these changes helps you or your clinician decide if the drug is safe for your situation.

How Aromatase Inhibitors Work

Aromatase is an enzyme that turns other hormones into estrogen. Drugs like anastrozole, letrozole, and exemestane block this enzyme, so less estrogen is made. With less estrogen, many breast cancers shrink or stop growing. The drugs are taken once a day as a pill, and most people tolerate them well. Common side effects include joint pain, hot flashes, and mild bone loss. Your doctor will likely order bone density scans and may suggest calcium or vitamin D supplements to protect your bones.

Bleeding Risk and the CRUSADE Score

One thing that doesn’t get talked about enough is how aromatase inhibitors can affect bleeding risk. Estrogen helps keep blood vessels flexible and supports normal clotting. When estrogen drops, some patients notice easy bruising or longer nosebleeds. For clinicians who use the CRUSADE bleeding score—a tool that predicts bleeding risk in patients on certain heart meds—adding an aromatase inhibitor can push the score higher. That means extra caution is needed if the patient also takes blood thinners, antiplatelet drugs, or has a history of ulcers.

When you or your doctor calculate the CRUSADE score, look at factors like age, blood pressure, kidney function, and current medications. If an aromatase inhibitor is part of the mix, note it as a possible contributor to higher bleeding risk. Some doctors choose to monitor blood counts more often or switch to a different cancer therapy if the bleeding risk becomes too high. The key is open communication: tell your healthcare team about any unusual bruising, bleeding gums, or prolonged bleeding after cuts.

In practice, most patients on aromatase inhibitors never experience serious bleeding. Still, staying alert can catch problems early. Simple steps like avoiding unnecessary NSAIDs, using a soft toothbrush, and keeping a list of all medications handy can make a big difference. If you’re starting an aromatase inhibitor, ask your doctor how the drug might affect your CRUSADE score and what monitoring plan they recommend.

Bottom line: aromatase inhibitors are powerful tools against hormone‑positive breast cancer, but they do change how your blood clots. Knowing the basics, watching for signs of bleeding, and using the CRUSADE score wisely can keep you safe while you fight cancer. Have more questions? Talk to your pharmacist or oncologist – they can break down the risks and help you stay on track.