for many prescription nexium helps heal acid-related erosions in the lining of the esophagus. it's my prescription. there is risk of bone fracture low magnesium, and vitamin b12 deficiency. side effects include headache abdominal pain and diarrhea. if persistent, contact your doctor right away. other serious stomach conditions may exist. avoid if you take clopidogrel. it's my prescription. nexium 40mg is available only by prescription. pay only $15 a month. visit purplepill.com today.