Nexium (esomeprazole) is a prescription drug intended for gastroesophageal reflux disease, although it may also be used to prevent ulcers. Your doctor will prescribe this medicine if he thinks it will be efficient for you. Make sure you always take the exact amount prescribed, usually once a day before having a meal. If you took more of Nexium than prescribed and have symptoms such as headache, fast heartbeat, confusion, sweating, dry mouth, flushing, drowsiness, nausea, or blurred vision, seek emergency medical help, as those symptoms indicate an overdose and need to be reported to your local emergency center. Both mild and more serious side effects are possible. Mild side effects include stomach pain, gas, nausea, diarrhea, dry mouth, constipation, and headache and do not need to be reported, while serious side effects, such as hives, hoarseness, swelling of the face, throat, hands or feet, itching, difficulty breathing or swallowing, rash, blisters or peeling skin, are to be reported to your doctor right away. If you are going to take any new drugs, report that fact to your doctor, the following ones will be important to mention: antifungals, clopidogrel, atazanavir, digoxin, iron supplements, anticoagulants, and other over-the-counter or prescription products.