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Side Effects of Esomeprazole (Nexium)


Esomeprazole (Nexium), is a prescription drug belonging to a class of medications called proton pump inhibitors (PPIs). These medications reduce the amount of acid in your stomach. Esomeprazole is used to treat the symptoms of gastroesophageal reflux disease (GERD); reduce the risk of stomach ulcers in some people experiencing side effects from non-steroidal anti-inflammatory drugs ( NSAIDs); treat patients with a stomach infections due to helicobacter pylori bacteria and long-term conditions where your stomach makes too much acid, including Zollinger-Ellison Syndrome.

Serious Side Effects of Nexium

According to the Nexium Medication Guide as reported by FDA (2014), serious reactions to Nexium include chronic inflammation of the stomach lining (atrophic gastritis) and low magnesium levels in your body. Symptoms of low magnesium include: seizures, dizziness abnormal or fast heartbeat, and jitteriness. Kidney damage from PPIs over time can also occur.

Common Side Effects of Nexium

Commonly reported adverse drug reactions, according to the Nexium Medication Guide as reported by the FDA (2014), include: headaches, abdominal pain, constipation, diarrhea, nausea, gas, dry mouth and drowsiness.


People who take a proton pump inhibitor for more than one year, may be prone to get fractures of the hip, wrist or spine. Therefore, it is important to take esomeprazole exactly as prescribed by your doctor.


Esomeprazole reduces the amount of acid in your stomach which is needed to absorb Vitamin B12 adequately in the body. This can cause vitamin B12 deficiency if you take esomeprazole for an extended period of time.

Understand Your Risks with the Rxight® Genetic Test

Rxight® tests your individual genetic ability to metabolize hundreds of clinically significant prescription and over-the-counter medications. A simple cheek swab of your DNA is all that is required for us to analyze your genotype to determine how well you metabolize over 200 different medications across 50 significant pharmacological classes. After your specimen is analyzed, you will receive a report detailing the medications you are likely to have an adverse reaction to, those which may be ineffective and those which are safe at standard doses. With this Rxight® “medication blueprint” you and your care team can adjust your medication dosages accordingly or find safer alternatives if needed, instead of relying on the trial and error process.

How Does Pharmacogenetic Testing Work?

Esomeprazole is metabolized by CYP2C19 and CYP3A4, according to the esomeprazole drug label as reported by the FDA (2014). Of these, CYP2C19 activity varies considerably due to genetic differences. Some individuals with low to minimal activity of CYP2C19 are also known poor metabolizer. They are exposed to high blood levels of esomeprazole making them prone to experience adverse reactions. Rxight® genetic testing of CYP2C19 can provide key information to healthcare providers to possibly individualize esomeprazole therapy.


Contributors to this Article:
Michael Sapko, MD, PhD; Deborah Kallick, PhD, Medicinal Chemistry


Read more about Rxight® genetic testing