Nexium (esomeprazole) is generally well tolerated in the short term, but it carries a range of side effects that become more concerning the longer you take it. The most common issues, like headache and diarrhea, affect roughly 4 to 6 percent of users. The more serious risks, including kidney problems, bone fractures, and nutrient deficiencies, are tied to prolonged use lasting a year or more.
Common Side Effects
In clinical trials of adults, the side effects reported most often were headache (about 5.5%), diarrhea (4.3%), and abdominal pain (3.8%). Nausea also shows up in a small percentage of users. These tend to be mild and often resolve on their own or shortly after stopping the medication.
When Nexium is taken alongside antibiotics to treat stomach ulcers caused by H. pylori (a 10-day “triple therapy” regimen), side effects are more frequent. Diarrhea jumps to about 9%, and roughly 7% of people experience an unpleasant or altered taste. Abdominal pain affects close to 4%. These higher rates are partly due to the antibiotics, not Nexium alone.
In teenagers, headache rates were notably higher at around 8%. Children aged 1 to 11 experienced diarrhea (2.8%), headache (1.9%), and drowsiness (1.9%).
Kidney Damage
One of the more serious risks is a condition called acute interstitial nephritis, where the kidneys become inflamed. It’s rare, but it can lead to lasting kidney damage if it isn’t caught early. By 2004, the manufacturer had identified at least 15 cases worldwide linked to esomeprazole specifically. In one hospital study of patients with unexplained acute kidney failure who underwent biopsy, drug-induced kidney inflammation accounted for 8% of cases, and PPIs were responsible for more than half of those.
The tricky part is that there’s no clear threshold for when this happens. Researchers still don’t fully understand whether longer use or higher doses make it more likely. Symptoms can include decreased urine output, swelling, fatigue, or unexplained changes in kidney function on blood tests. If you’ve been on Nexium for a long time and notice these kinds of changes, it’s worth having your kidney function checked.
Bone Fracture Risk
Taking Nexium for longer than a year, especially at high doses, is associated with a modest increase in the risk of hip, wrist, and spine fractures. Two large meta-analyses put the increased risk at 10 to 40% above baseline. That sounds alarming, but context matters: if your baseline risk of a hip fracture is low, a 10 to 40% increase on top of that is still a relatively small absolute number. The risk is most relevant for older adults, people already prone to osteoporosis, or anyone on high doses for extended periods.
Gut Infections
Stomach acid serves as a natural barrier against harmful bacteria. By suppressing that acid, Nexium can make you more vulnerable to certain infections. The most concerning is Clostridioides difficile (C. diff), a bacterial infection that causes severe, sometimes dangerous diarrhea. Research shows the risk of C. diff increases in a dose-dependent way: more medication and longer use both nudge the risk upward. Each additional day of PPI therapy adds a small but cumulative increase in risk. This is especially relevant if you’re in a hospital setting, taking antibiotics, or are older.
Nutrient Deficiencies
Because stomach acid helps your body absorb certain nutrients, long-term acid suppression can create deficiencies over time. Two are worth knowing about.
Vitamin B12 deficiency can develop after taking Nexium daily for a year or more. B12 is essential for nerve function and red blood cell production. Low levels can cause fatigue, numbness or tingling in your hands and feet, memory problems, and difficulty with balance. The risk is higher in older adults, who already tend to absorb less B12.
Low magnesium is another recognized complication. The FDA has issued warnings about dangerously low magnesium levels in people taking PPIs for extended periods. Symptoms include muscle cramps, tremors, irregular heartbeat, and seizures in severe cases. This side effect is uncommon but potentially serious, and it doesn’t always show up on routine blood work unless your doctor specifically tests for it.
Cardiovascular Concerns
Research published in the American Heart Association’s journal Circulation identified a biological mechanism by which PPIs, including esomeprazole, may affect heart health. These drugs appear to raise levels of a substance in the blood called ADMA, which interferes with nitric oxide production. Nitric oxide keeps blood vessels relaxed and healthy. In lab studies, PPIs increased ADMA levels by about 30%, an elevation that has been linked to a 30% increase in major cardiovascular events over long follow-up periods.
This concern is most relevant for people who already have heart disease, particularly those recovering from a heart attack or with unstable coronary syndromes. For the average person taking Nexium for heartburn, the absolute cardiovascular risk is likely small, but it’s another reason not to stay on the drug longer than necessary.
Interaction With Blood Thinners
If you take clopidogrel (Plavix), a common blood-thinning medication used after heart attacks or stent placement, Nexium is a poor companion. Both drugs compete for the same liver enzyme to be activated. When taken together, Nexium can reduce how effectively clopidogrel prevents blood clots. The FDA has placed a boxed warning (its strongest type) advising against using esomeprazole and clopidogrel together. If you need acid suppression while on clopidogrel, other options that don’t interfere with this enzyme are available.
Dementia Risk Is Likely Overstated
You may have seen headlines linking PPIs to dementia. Earlier observational studies raised this concern, but stronger evidence has not supported it. A well-designed prospective study of nearly 19,000 older adults, followed for a median of 4.5 to 6.3 years, found no association between PPI use and dementia after adjusting for factors like education, kidney disease, diabetes, and family history. The adjusted risk ratio was 0.88, meaning PPI users actually had a slightly (though not statistically significant) lower rate of dementia than nonusers. The earlier alarming findings likely reflected flaws in study design, such as failing to account for other health conditions that independently raise dementia risk.
Rebound Acid When You Stop
Stopping Nexium abruptly after taking it for a while can trigger what’s known as rebound acid hypersecretion. Your stomach temporarily produces even more acid than it did before you started the drug. This happens because long-term acid suppression prompts your body to ramp up production of gastrin, a hormone that stimulates acid release. When the medication is suddenly removed, all that extra gastrin drives acid levels above your original baseline.
This rebound typically begins within two weeks of stopping and can cause heartburn, acid reflux, or stomach discomfort that feels like your original problem has returned, sometimes worse than before. It’s a common reason people restart the medication unnecessarily, believing they still need it. Tapering your dose gradually rather than stopping cold turkey can help minimize this effect.