This is a spontaneous report from a contactable consumer (patient's wife). A male patient of an unspecified age received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE), dose 1 via an unspecified route of administration on an unspecified date (Batch/Lot Number: Unknown) as single dose for COVID-19 immunization. Medical history included dementia and he shrunk he is 5'9" or 5'8". Concomitant medication(s) included warfarin sodium (COUMADIN), at 4 mg once daily in the evening 6 days per week, On Fridays he takes 6 mg once in the evening. Patient's wife says her husband had one vaccination, the Pfizer vaccine and a week later her ended up in the hospital. They had to postpone his second dose because he ended up in the hospital but they have the second one coming up on the 14May2021 and she is scared for him to get it, he is adamant he is going to take it. He was taking her to the doctor for a problem she had and he told her he could not go to the bathroom and she was like what, because he has a stoma bag and she looked and it was plugged with a blood clot, he couldn't open it and drain it so she told him to get in the shower and take it off and put a new one on and she was pulling it off, it was full of blood and there was a big huge, like real liver sized clot came out of his stoma bag. She went to get the stoma bag after the thing came off she grabbed it and got it in the bag and took it out. He was taken to the hospital by the paramedics and he spent 3 days in the hospital. He is 83 now but this happened the week before his birthday, he was 82 when they noticed the blood in his stoma bad, he was a week away from 83. She provides his height and says he shrunk he is 5'9" or 5'8". She does not remember the date of the first dose. She says his birthday was 18Apr2021. She thinks he was admitted to the hospital on 12Apr2021 and he got the first dose the week before that. She thinks it was 12Apr2021 that he was admitted because it was just before birthday first dose week prior to that. They never made the connection. She thinks he ended up in the hospital on a Tuesday and she is trying to count from his birthday 18Apr2021, she thinks he got to come home on Thursday, 15Apr2021. She believes he went in on 12Apr2021 and was discharged on 15Apr2021, he was there 3 days. No further information provided. Her husband is not there with her. She does not have his vaccine card to provide NDC lot expiration or dose amount. he may not even have his vaccine card because he has dementia. No further information provided.  He hardly takes any mediation He takes Coumadin he takes 1 per day except Fridays he takes 2, she thinks it's 4 mg and he takes 2 at night everyday except Friday he takes 3. she was guessing. She has one there called Atorvastatin that says it is for Lipitor, so that is not it. She sees Glipizide. No further information provided. She says she found the Coumadin, they are 2mg tablets and he takes 2 at night. She says the dose is not written on there because they call him every 3 weeks because he has to have a blood draw. He takes 2 tablets at night 6 days per week. She clarifies he takes 4 mg once daily in the evening 6 days per week and on Friday he takes 6 mg once in the evening.  They just got report for that and it was 1.8 which is a little bit low but he lost blood and had to have a transfusion while in the hospital. It is in a white plastic bottle they got it from (Name). NDC 0093-1713-01 she does not see anything else. She thinks the pharmacy label is wrapped almost all the way around the bottle but she does not see lot number expiration. She sees they ordered it 11Feb2021 and she has a quantity that is it. Treatment received and outcome was unknown. Information on the lot/batch number has been requested.