I started on biaxin (clarithromycin) xl for a sinus infection. i was urinating and went to wipe and noticed red blood on tissue and in toilet. is this a side effect?

On Anticoagulation?: If you are taking a blood thinning agent like warfarin, the antibiotic may be decreasing your ability to clot; talk to your doctor or allied health professional about it.

No: If you are having blood in the urine you need to be seen by a doctor and re-evaluated. Am assuming, since you were wiping, that you are a woman. Are you sure the blood is not vaginal?