Weight: Gained 25lbs; Arm is slightly tender; arm might get a little stiff; excruciating leg cramping going from her buttock down behind her knee and rolling to the inside of her thigh/the same pain occurred on the opposite leg around noon and lasted for 15 minutes; excruciating leg cramping going from her buttock down behind her knee and rolling to the inside of her thigh/the same pain occurred on the opposite leg around noon and lasted for 15 minutes; the inside of her thighs were a little red on the side, both legs from her thighs to her knees; the shot is already fogging her mind; This is a spontaneous report from a contactable consumer (patient). A 69-year-old female patient received the first dose of NT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Solution for injection), via an unspecified route of administration, administered in left arm on 26Mar2021 08:30 (Lot Number: ER8727; Expiration Date: 31Jul2021, at age of 69 years old) at a single dose for covid-19 immunization. Medical history included allergies: Penicillin, Ampicillin, hair color product. The patient's concomitant medications were not reported. She was allergic to Penicillin, and Ampicillin. As a child, always reacted strongly to any vaccination she was given with a fever and flu like symptoms for a couple of days. With Ampicillin, she thought she was having a heart attack. Was told to stop Ampicillin immediately because she could get a heart attack. This was when she was 25 years old and she never went to the ER. She was allergic to a hair color product in the 1990s and it made her scalp itch really badly. Was given a cortisone shot, which she reacted immediately breaking out head to toe in hives. Has no NDC/LOT/EXP for the vaccinations she reacted strongly to as a child. Stated this was in the 1950s or early 1960s. Clarified she did not have a heart attack with Ampicillin, but it felt like she was having one. Has had cardiograms per her request and her heart and heart walls are perfect. The patient received the first dose of the Covid vaccine at 8:30 a.m. this morning on 26Mar2021. Caller reports around 11 a.m., she experienced excruciating leg cramping going from her buttock down behind her knee and rolling to the inside of her thigh, states that the pain lasted 15 minutes. The patient reports the same pain occurred on the opposite leg around noon and lasted for 15 minutes, states that "the pain was so excruciating that she could barely stand up and it was so agonizing it was unbelievable." The patient noticed that the inside of her thighs were a little red on the side, both legs from her thighs to her knees. The patient states that she has not been in the sun, and didn't think it was anything alarming, but this is abnormal for her, states that she received the vaccine in the right arm and her upper torso is fine and her head is clear, asked if anyone else had reported this reaction. She was planned to received the second dose on 16thApr in the early afternoon. The patient stated the COVID shot was already fogging her mind. The patient felt pretty good after first shot. Felt nothing. Fifteen minutes before leaving the diner she got a leg cramp. Was sitting in a booth and didn't think much of it. Attributed it to the way she was sitting. Around 11AM when she got back to her garage, she was in agony. It hurt from the top of her rear all the way down the side to the back of her knee and rolled to the inside of her thigh. She was in such agony and didn't know if she could get out of her chair and walk. By the time she reached her apartment it has subsided. An hour later, same thing happened in the left leg. She was laying in bed and texting because she didn't' know if she would get any other reaction. This leg cramp was even worse. She was in tears. Got off bed to try and walk it off. Initial leg cramp happened in right leg. Was excruciating. Both times it lasted for 15 minutes. Both cramps were from her buttocks, all down to her knees, and rolled over into her thigh. Didn't know if that was a reaction. It is not typical of anything written on Pfizer's information or that she had heard. She was concerned. Heard about blood clots, but not with this particular product. Stated second leg cramp subsided. If it hadn't, she wouldn't have gone to the ER. Leg cramps was so excruciating. Originally thought it was coincidental and stated she will be 70 on (Date withheld). To say she has never had leg cramps before would be a lie. The way the leg cramps were timed was kind of weird. It was absolutely the same kind of cramp and location just on the a different leg. Weight: Gained 25lbs. Doesn't have COVID or any symptoms. Tested three to four months ago and was negative. Received first dose COVID-19 Vaccine today, 26Mar2021, at 08:30AM. First leg cramp began 11:00AM in right leg. Second leg cramp began Noon in left leg. Each time lasted 15 minutes. Not having leg cramps right now. Could barely talk when having leg cramps. Was worried about getting clots in legs. Otherwise she would think it was because she was getting older. She doesn't get leg cramps very often. Doesn't know when the last time she had leg cramps prior to today. Nurse technician at vaccine faculty stated caller's allergy history wouldn't be a problem and she only had to sit for 15 minutes. Received the COVID-19 Vaccine and hardly felt it. Waited for 15 minutes. She was fine until 11AM. She was fine now, but her arm might get a little stiff tomorrow. Arm was slightly tender. Surprised she felt something in her legs. Doesn't know whether to associate it with COVID-19 Vaccine or not. Has nothing to complain about in the upper torso or from the waist up. Wants to know if this is a reaction or coincidence. Stated she expected to have a stiff arm. The outcome of the event "Cramps in legs" and "pain" was recovered on 26Mar2021. The outcome of other events was unknown.