@rmig I have never seen that set of problems arise from a patient on apixaban, but we're all individuals with individual 'negotiations' going on inside of us when we take a drug or a cocktail of them. You may need probiotics, maybe consume some kimchi or kombucha, or even a temporary fast might help (at least 48 hours, longer if you can*...). Note that these are what I would try, having some experience with this, and that I am not suggesting you SHOULD DO IT AS WELL: I am not qualified to give any medical advice, only to relate my own experience.

Even then, an endoscopy might show something right out of the blue. Please consult a physician about these symptoms.

* Fasting isn't just stopping eating. After a while it can disrupt electrolyte imbalance, so every 12 hours or so you need to drink a sport drink with no sugars (NUUN tablets dissolved). Read up on 'How to fast successfully' before you attempt this....IF....you attempt to do this. Fasting can help to repair the stomach lining if it goes on long enough, for example.