Does Eliquis Cause Black Stools?
Yes, Eliquis (apixaban) can cause black stools. This side effect stems from its action as a blood thinner (anticoagulant), which increases bleeding risk. Blood in the stool from gastrointestinal bleeding oxidizes in the digestive tract, turning stools black and tarry—a condition called melena.[1][2]
Why Does This Happen with Eliquis?
Eliquis inhibits factor Xa, a protein in the clotting process, making it harder for blood to clot. Minor bleeds in the stomach or intestines go unnoticed initially but produce dark stools as hemoglobin breaks down. Risk rises with higher doses, age over 75, kidney issues, or concurrent use of NSAIDs, aspirin, or other anticoagulants like warfarin.[3][4]
How Common Is It?
Black stools occur in about 1-10% of Eliquis users, based on clinical trials and post-marketing reports. Major gastrointestinal bleeding, which can cause this, affected 0.76% per year in pivotal trials like ARISTOTLE, compared to 0.86% for warfarin.[5][6] Real-world data shows higher rates in older patients or those with ulcers.
What Should You Do If You Notice Black Stools?
Seek immediate medical attention. It signals potential internal bleeding needing tests like endoscopy. Do not stop Eliquis abruptly without doctor guidance, as this risks clots. Doctors may switch to reversal agents like andexanet alfa or adjust doses.[7][8]
How Does Eliquis Compare to Other Blood Thinners?
Eliquis has a lower gastrointestinal bleeding risk than warfarin (25% reduction in trials) but similar to Xarelto (rivaroxaban). Pradaxa (dabigatran) shows higher rates in some studies. All can cause black stools, but Eliquis's twice-daily dosing and no routine monitoring appeal to patients despite bleed risks.[9][10]
Who Is at Higher Risk?
Patients with:
- History of ulcers or GI bleeds
- Use of steroids, SSRIs, or clopidogrel
- Low body weight or anemia
- Poor kidney function (dose adjustments needed for CrCl 15-29 mL/min)
Monitoring includes regular blood tests for hemoglobin.[11]
Preventing Black Stools on Eliquis
Take with food to reduce stomach irritation. Avoid alcohol excess, falls, and unapproved supplements like fish oil. Proton pump inhibitors (PPIs) like omeprazole may help high-risk patients, though evidence is mixed due to potential clot risk interactions.[12][13]
Sources
[1]: FDA Eliquis Label
[2]: Mayo Clinic - Apixaban Side Effects
[3]: Drugs.com - Eliquis Side Effects
[4]: Medscape - Eliquis Dosing
[5]: ARISTOTLE Trial - NEJM
[6]: Drugs.com - Eliquis vs Warfarin
[7]: American Heart Association - Anticoagulant Bleeding
[8]: UpToDate - Apixaban Management
[9]: Lancet - DOAC Bleeding Comparison
[10]: GoodRx - Blood Thinner Comparisons
[11]: Bristol Myers Squibb - Eliquis Prescribing Info
[12]: NIH - PPI-Anticoagulant Interactions
[13]: Cleveland Clinic - Blood Thinner Precautions