INCREASE IN BEING OFF BALANCE; FELL 3 TIMES; WHOLE BODY WAS IN A KNOT AND TENSE DUE TO PAIN; NEUROPATHY WORSENED; COULD NOT FUNCTION NORMALLY IN THE DAY; This spontaneous report received from a patient concerned a 59 year female. The patient's weight was 186 pounds, and height was 64 inches. The patient's concurrent conditions included: multiple sclerosis, non-alcohol user, non-smoker, neuropathy in legs. Other pre-existing medical conditions included: No history of drug abuse or illicit drug use. The patient received covid-19 vaccine (suspension for injection, route of admin not reported, batch number: 207A21A, expiry: 21-SEP-2021) dose was not reported, 1 total administered on 18-MAY-2021 at left arm for prophylactic vaccination. Concomitant medications included acetylsalicylic acid, and gabapentin. In MAY-2021, Within a couple days of getting the vaccine, patient's neuropathy worsened and became pronounced and intense. By the end of the second week, she noted the increase in pain. Laboratory data included: Pain scale (NR: not provided) 3-4 out of 10. A mid day dose of 300 mg of gabapentin was added some time in JUN-2021. Laboratory data included: MRI (NR: not provided) No inflammatory response and everything seemed quiet. It became a screaming ache that lasted until the end of JUL-2021. The pain became 8-9 out of 10 on the pain scale after she received the vaccine. Post vaccine, the intensity was at the point where she could not function normally in the day like she could before with nerves in her legs firing all the time with intensity that was not there before the vaccine. She also started physical therapy in JUL-2021 because she felt like her muscles got weak and she did not wanted to loose the ability to walk because she always sat due to pain and intense firing of muscles. The evening dose of gabapentin was increased to 450 mg in mid JUL-2021. At end of JUL-2021, the pain subsided but it was more intense then before vaccine levels at the time of reporting. The neurologist said that he had increased the gabapentin dosages as her whole body was in a knot and tense due to pain. The gabapentin had to be increased to make it more manageable but it had brought on balance issues. Previously, she took 300 mg of gabapentin at night only. She took 600 mg at night and 300 mg mid day at the time of reporting. The pain was more manageable and she could breathe at the time of reporting. Then, it was increased to 600 mg at the beginning of AUG-2021. She had not been to the emergency room or any urgent care centers. She fell three times due to the pain intensity. The pain was so bad that she could not keep her balance or keep herself from falling. She could lift her feet much better than she could in the first two months at the time of reporting. She walked and was more active at the time of reporting. She noticed an increase in being off balance. She noticed this after increasing the dose of gabapentin. Her physician recommended 450 mg at bedtime and she wanted 600 mg at bedtime because 450 mg was not enough to relieve the pain. The neurologist said she could have started experiencing balance issues at this dosage. She stated that she had always been off balance as part of her multiple sclerosis condition, but this was more severe at the time of reporting. The action taken with covid-19 vaccine was not applicable. The outcome of the neuropathy worsened, whole body was in a knot and tense due to pain, increase in being off balance, fell 3 times and could not function normally in the day was not reported. This report was serious (Other Medically Important Condition).; Sender's Comments: V0:20210827099-COVID-19 VACCINE -Neuropathy worsened. This event(s) is considered unassessable. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s).