What problems can lansoprazole cause?

October 13, 2025 •

3 min read

Globally, proton pump inhibitors (PPIs) like lansoprazole are among the most heavily prescribed drugs, but concerns persist about potential adverse effects. While lansoprazole is generally well-tolerated, understanding what problems can lansoprazole cause is crucial, particularly concerning long-term use, serious complications, and drug interactions.

Quick Summary

Lansoprazole, a PPI, can cause common side effects like headache and diarrhea, as well as more serious problems, including low magnesium, vitamin B12 deficiency, and an increased risk of bone fractures and kidney injury, especially with prolonged therapy. It also carries a risk of severe infections like C. difficile and has notable drug interactions.

Key Points

Common Side Effects: The most frequent issues with lansoprazole are typically mild and include headaches, dizziness, diarrhea, nausea, and abdominal pain.
Long-Term Mineral Deficiencies: Prolonged use can lead to serious deficiencies in magnesium and vitamin B12, causing symptoms such as muscle cramps, tremors, and nerve issues.
Increased Fracture Risk: Taking lansoprazole for extended periods, especially at high doses, has been linked to an increased risk of bone fractures, particularly in the hip, wrist, and spine.
Risk of Serious Infections: Reducing stomach acid increases susceptibility to severe gut infections like C. difficile-associated diarrhea, which can be life-threatening.
Potential Kidney Damage: Long-term lansoprazole use has been associated with an increased risk of developing kidney problems, including acute and chronic kidney disease.
Significant Drug Interactions: Lansoprazole can affect the effectiveness of other medications, including certain HIV drugs, methotrexate, and blood thinners like warfarin.
Cognitive and Neurological Effects: While studies show conflicting evidence, some research suggests a potential link between long-term PPI use and neurological or cognitive issues, warranting cautious use and monitoring.

Understanding Lansoprazole and Its Function

Lansoprazole is a proton pump inhibitor (PPI) that works by reducing the amount of acid produced in the stomach. It is prescribed to treat conditions such as gastroesophageal reflux disease (GERD), erosive esophagitis, stomach ulcers, and Zollinger-Ellison syndrome. While effective, its potent and prolonged acid-suppressing action can lead to a range of potential side effects and health complications, which can differ based on the duration of use.

Common and Short-Term Side Effects

For many people, lansoprazole is a safe and effective medication, and any side effects experienced are usually mild and temporary. These effects often appear during the initial treatment period and may resolve on their own as the body adjusts to the medication. Common side effects include:

Headaches and dizziness
Diarrhea, constipation, or abdominal pain
Nausea and vomiting
Dry mouth or dry throat
Gas or flatulence
Skin rashes and itching

Long-Term and Serious Complications

While short-term use is generally safe, the risk of serious problems increases with long-term lansoprazole therapy (typically defined as more than one year). Patients on prolonged regimens should be regularly monitored by a healthcare provider for potential complications.

Low Magnesium Levels (Hypomagnesemia)

Long-term use, especially for over a year, can lead to severely low magnesium levels in the blood. This condition can cause serious issues, including seizures, muscle spasms, irregular heartbeat, and tremors. The FDA has warned that in some cases, magnesium supplements alone are not enough to correct the deficiency, and the PPI must be discontinued.

Vitamin B12 Deficiency

Long-term use (more than three years) of lansoprazole can lead to vitamin B12 deficiency due to reduced stomach acid affecting absorption. Symptoms include fatigue, weakness, and neurological issues.

Increased Risk of Bone Fractures

Long-term, high-dose PPI use may increase the risk of hip, wrist, and spine fractures, particularly in older adults, possibly due to reduced calcium absorption. The FDA has issued a safety warning regarding this risk.

Fundic Gland Polyps

Long-term lansoprazole use can cause benign fundic gland polyps in the stomach lining, which are usually asymptomatic.

Clostridioides difficile Infection

Lansoprazole use can increase the risk of severe C. difficile infection, characterized by severe diarrhea, abdominal pain, and fever. The FDA has noted this increased risk with PPI use.

Potential for Kidney Problems

Studies link PPI use, including lansoprazole, to an increased risk of kidney damage, especially with long-term use. Risks include Acute Interstitial Nephritis, Acute Kidney Injury, and Chronic Kidney Disease.

Important Drug Interactions

Lansoprazole can interact with various medications, affecting their effectiveness. Notable interactions include certain HIV drugs, methotrexate (increasing toxicity risk), warfarin (increasing bleeding risk), clopidogrel (reducing antiplatelet effect), antifungal medications like ketoconazole and itraconazole (reduced absorption), and St. John's wort (reducing lansoprazole's effectiveness).

Considerations for Prescribing and Use


Factor	Short-Term Use (typically < 1 year)	Long-Term Use (typically > 1 year)
Common Side Effects	Headache, dizziness, diarrhea, nausea, stomach pain.	Headache, dizziness, diarrhea, nausea, stomach pain may persist or change.
Mineral Deficiency	Rare occurrence of low magnesium or vitamin B12.	Increased risk of low magnesium (hypomagnesemia) and vitamin B12 deficiency.
Infections	Low risk of C. difficile infection.	Increased risk of serious gut infections, including C. difficile.
Kidney Risks	Risk is generally low; however, Acute Interstitial Nephritis can occur at any time.	Increased risk of Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD).
Bone Health	Negligible impact on bone mineral density or fracture risk.	Increased risk of hip, wrist, or spine fractures, especially in older adults.
Stomach Growths	Not typically associated with fundic gland polyps.	Increased risk of fundic gland polyps.

Conclusion

Lansoprazole effectively treats acid-related conditions, but its use, especially long-term, carries risks. Potential problems include deficiencies in magnesium and vitamin B12, increased risk of bone fractures, C. difficile infection, and kidney damage. It also interacts with many medications. Using the lowest effective dose for the shortest duration and discussing treatment with a healthcare provider minimizes these risks. Patients should report any persistent symptoms. Informed discussion ensures safe treatment.

Frequently Asked Questions

The most common side effects of lansoprazole include headache, dizziness, diarrhea, nausea, abdominal pain, and constipation. These effects are typically mild and often improve as your body adjusts to the medication.

Yes, long-term use (typically over a year) is associated with several potential health problems. These include low magnesium and vitamin B12 levels, an increased risk of bone fractures, and kidney problems.

By reducing stomach acid, lansoprazole can increase the risk of a severe intestinal infection called C. difficile, which causes persistent, watery diarrhea, abdominal pain, and fever. The risk is particularly elevated with prolonged use.

Some studies have suggested a potential link between long-term PPI use and cognitive decline or dementia, although the evidence is conflicting. More research is needed to determine the relationship, but it remains an area of concern for older adults on long-term therapy.

Yes, prolonged use of lansoprazole has been linked to an increased risk of acute kidney injury (AKI), chronic kidney disease (CKD), and a condition called acute interstitial nephritis (AIN). If you notice a decrease in urination or have blood in your urine, contact your doctor immediately.

Lansoprazole interacts with several medications, including certain HIV drugs, methotrexate, warfarin, and antifungals like ketoconazole, which can alter their effectiveness or increase toxicity. Always inform your doctor and pharmacist of all medications you are taking.

You should not stop taking prescribed lansoprazole without first consulting your doctor. Sudden cessation can cause a rebound effect of increased stomach acid. Your doctor may recommend a gradual reduction in dose or an alternative treatment.

Yes, lansoprazole is generally considered safe for short-term use as prescribed, such as for a 14-day course for frequent heartburn. The more serious risks are primarily associated with long-term, high-dose therapy.