Hi there, It s likely not the BP meds that are the problem. The most common cause of rectal bleeding is hemorrhoids. If he has bright red bleeding after he wipes, that s likely the cause. His drinking history makes things more complicated, as he may have varices (dilations of the veins) in his esophagus or stomach, which are caused by portal hypertension (increased pressure in the blood system of the liver). This is because the liver becomes harder (cirrhotic) and blood doesn t decompress in the system as well. The first I d recommend is that he continue to take his blood pressure medication. This isn t the cause. The second thing I d recommend is that he start taking some kind of acid reducing medication for his stomach - prilosec may help. The third thing I would recommend is that he have his doctor check his liver enzymes and perform an ultrasound of his liver. Finally, he should have both a colonoscopy and and endoscopy to evaluate where the bleeding is coming from. I hope this answers your questions. Please feel free to contact me should you have any further questions.