Feeling hot and cold; Cramping; He lost weight in the hospital; He wasn't feeling well; He just had the feeling of being tired; blockage in the lower intestines.; Hard time going to the bathroom; This is a spontaneous report from a contactable consumer (patient) via medical information team. A 64-year-old male patient received first dose of bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE, formulation: solution for injection, #lot number:ER8732) via an unspecified route of administration administered in left arm on 16-Apr-2021 at 10:30 (at age of 64-years-old) as single dose for COVID-19 immunization. The patient's medical history and concomitant medications were not reported. Patient underwent lab test and procedures include cholesterol and result was unknown on unspecified and colonoscopy on 10May2021 result was unknown. It was reported that the patient received the first dose of the Pfizer covid vaccine and was in the hospital for blockage in the lower intestines on 17Apr2021. The patient wanted to know if that is associated with the Pfizer covid vaccine. He stated his nephew was a police dispatcher and got a call where someone else have reported similar issue what the patient has experienced. The patient did not know what vaccine that person had or age and gender of that person. The patient wanted to know about if Pfizer was going to get the FDA approval for the Covid vaccine. The patient reported that he had both doses and he was fine right now but when he had the first dose he was, he got it 16Apr2021 and he had some side effects the next day, on 17Apr2021 he was having cramping and he woke up and was feeling hot and cold and ended up in the hospital with a blockage in his intestine and he was wondering if that could have been anything that was related the vaccine. The patient has lost weight in the hospital, he thinks he was about 145 lbs now. It was reported that the patient was fine the whole day he got the vaccine, he ran errands and did things he needed to do, he went to bed and woke up and felt hot and cold and on 17Apr2021, he was having hard time going to the bathroom. He called his son and told him he wasn't feeling well on an unspecified date in Apr2021 and his son came over and called his other son who is a fireman and he told them to call the ambulance so they did and they took him to the hospital and they couldn't figure out, he was asking them and they had no answer, he just seen on the website and he has been wanting to call but he wasn't going to but he did so that they would have it documented. He confirms when the cramping and feeling of hot and cold and difficulty using the bathroom began it was after midnight and the date was 17Apr2021. When asked if the feeling of hot and cold is ongoing, he says he was in the hospital for 8 days. When asked if the feeling of hot and cold is ongoing or has it recovered, he says he just had the feeling of being tired on an unspecified date in Apr2021 and out of it even after the fact. He does not if it had to do with vaccine or if it was something, he had going on prior to that. The ER doctor told him it was possible that when he got the vaccine whatever could have been going on and put his system in overload. He confirms he was admitted to the hospital due to blockage in the intestine supposedly, the lower intestine. He says that is recovered, everything got taken care of, he had to schedule a colonoscopy after he got out of the hospital. He does not know why they couldn't have done it there while he was in the hospital. He was contemplating the second dose; it was scheduled on 07-May-2021 and he had his scheduled colonoscopy for 10-May-2021 and he didn't know what he should do. People were telling him do it or not to do it but his doctor told him to go ahead and get it so he followed what he said and he did get it. The hospitalization dates were from 17Apr2021 until 24Apr2021 was the day that he got out. He had blood work done for cholesterol in the hospital and he sees a cardiologist doctor for the cholesterol. They did blood work in the hospital every day, he has no idea what the results were. The events feeling hot and cold, cramping and hard time going to the bathroom after midnight and the middle of the night lead the patient to emergency room visit. He didn't know whether to call but it has been playing on his mind. He is sure they have given millions of doses and he did not know if it could be anything to do the vaccine. The outcome of events blockage in the lower intestines, feeling of hot and cold was recovered and outcome of other events was unknown.  Follow-up attempts are needed: Further information has been requested.