Dear Dr. Roach: I have a history of polyps. I recently had nasal polyps removed, and a previous colonoscopy had also revealed polyps. I have been put on a blood thinner (Xarelto) and an aspirin. Since I started taking Xarelto and the aspirin, my hemoglobin level dropped over the course of four months.
What is the best way to approach this? I have another colonoscopy scheduled again. The cardiologist thinks Xarelto is not the cause, even though my hemoglobin count was always in the normal range prior to starting Xarelto. — S.M.
Answer: Anticoagulants like warfarin (Coumadin) and rivaroxaban (Xarelto) act as kind of a “stress test” on your system in terms of bleeding. They themselves don’t cause bleeding, but if you have something like a polyp that easily bleeds, your body can’t stop the bleeding as well while on anticoagulants. You can lose blood faster than you can replenish it, especially if you are low on iron.
So, for people who are at the age where colon cancer is a concern (over the age of 45 for an average-risk person), a colonoscopy is a wise idea if you haven’t had one recently. Even people younger than 45, or people who have had a colonoscopy in the not-too-distant past, may still be recommended another look if there is no other explanation for the blood loss.
There are certainly other causes for a low hemoglobin count besides slow blood loss (so slow you aren’t seeing blood), including bone marrow diseases and problems absorbing nutrients like iron, B12 or folic acid. But, for those with a history of colon polyps, a colonoscopy is usually the critical first step.
