If your doctor approves, ask how often you should return for follow-up visits to assess whether continued Nexium use is necessary and to determine whether you are developing any side effects. Also ask your doctor about the symptoms of nutrient deficiency you should watch out for. Nexium’s serious side effects are rare. But they can be life-threatening if not treated. Other side effects of Nexium are more common. But they can be life-threatening if not treated. Other side effects of Nexium are more common. Nexium is a proton pump inhibitor (PPI), a drug with unwanted side effects. Find out how patients have been affected and the lawsuits they're pursuing. Find out how patients have been affected and the lawsuits they're pursuing. How to use Nexium Capsule,Delayed Release (Enteric Coated) Read the Medication Guide and the Patient Information Leaflet if available from your pharmacist before you start taking esomeprazole and. Common side effects associated with Nexium include dizziness, headache, diarrhea, constipation and dry mouth. Other less common side effects occurring in less than 1% of patients treated with. Along with its needed effects, esomeprazole (the active ingredient contained in Nexium) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. If you notice any of the following serious side effects, stop taking Nexium and contact a doctor immediately: Sudden wheezing, swelling of your lips, tongue and throat or body, rash, fainting or difficulties in swallowing (severe allergic reaction). Share your side effects or success stories. Take control of your health by being informed and asking questions. AskaPatient.com provides tools for the empowered patient. Take control of your health by being informed and asking questions. Nexium (esomeprazole magnesium) is a proton pump inhibitor that decreases the amount of acid produced in the stomach. Nexium is used to treat symptoms of gastroesophageal reflux disease and other conditions involving excessive stomach acid such as Zollinger-Ellison syndrome. Pictures of Nexium (Esomeprazole Magnesium), drug imprint information, side effects for the patient.