What is Omeprazole?

woman having heartburn while holding a burger

The Bottom Line

Omeprazole is a medication that decreases the amount of acid the stomach produces. Known as a “proton pump inhibitor”, omeprazole is used to treat acid reflux and gastrointestinal ulcers. Omeprazole is available over-the-counter and as a prescription medication, but should be used with caution due to its interactions with other medications and dietary supplements.

woman taking medicine before eating

What is omeprazole used for?

Omeprazole is used to treat acid reflux (gastroesophageal reflux disease), ulcers in the small intestine or stomach lining, erosive esophagitis, and other similar conditions. Omeprazole, esomeprazole (Nexium), and pantoprazole (Protonix) are members of the “proton pump inhibitor” or “PPI” class of drugs. Proton pump inhibitors work by binding to stomach enzymes to block the production of gastric acid. This decreases the amount of acid the stomach produces and often results in a decrease in acid reflux symptoms. 

What are the side effects of omeprazole? 

Common side effects of omeprazole include headache, abdominal pain, dizziness, drowsiness, diarrhea, constipation, gas, nausea and vomiting. These side effects tend to be temporary and may last for a few days to weeks after taking the medication. Serious side effects reported with long-term use of omeprazole include infections, low magnesium levels, weakened bones, vitamin B12 deficiency, and kidney problems. In addition to those side effects, people who suddenly stop taking omeprazole may produce too much stomach acid and develop a condition of acid rebound. Individuals who take omeprazole for at least 2 months and are ready to stop should speak with their doctor or pharmacist about the safest way to discontinue the medication. In some cases, this may include slowly lowering the omeprazole dose over 4 to 6 weeks.

Pantoprazole vs omeprazole vs esomeprazole: What are the differences?

Omeprazole, pantoprazole and esomeprazole are all proton pump inhibitors (PPIs) used to treat conditions like acid reflux. These medications work by decreasing the amount of acid the stomach produces. Omeprazole and esomeprazole are available as over-the-counter and prescription medications, whereas pantoprazole (Protonix) is available by prescription only. In one study, esomeprazole was found to provide the best control of stomach acid compared with other PPI’s, suggesting that this medication may be more effective in treating the signs and symptoms of acid reflux and related conditions. Another study suggests that omeprazole may be linked to more drug-drug interactions than pantoprazole. 

Is omeprazole safe for pregnancy? 

In animal studies, use of omeprazole during pregnancy was not associated with fetal harm. Because there are limited published studies concerning the effects of omeprazole on human fetal development, pregnant people should discuss the potential risks and benefits of this medication with their doctor, before taking this medication.

Is it safe to take omeprazole with other medications?

Omeprazole can have potentially dangerous interactions with the dietary supplement St John’s Wort and several medications including rifampin (an antibiotic to used treat tuberculosis), methotrexate (a chemotherapy drug), clopidogrel (a blood thinner), and HIV antiviral medications that contain rilpivirine. To avoid unwanted side effects, do not take omeprazole while taking any of these medications or supplements.

Can you drink alcohol with omeprazole?

Alcohol does not significantly interact with omeprazole, and it is safe to consume alcohol while taking omeprazole. However, because alcohol can cause an increase in gastric acid production, alcohol consumption may worsen the signs and symptoms of acid reflux. 

When is the best time to take omeprazole?

For best results, omeprazole should be taken before meals. Food can delay the body’s absorption of omeprazole by an average of 3-4 hours and can make the medication less effective. 

What should I do if I experience adverse effects while taking omeprazole?

If someone develops unexplained or unexpected symptoms after taking omeprazole, or if too much was taken, get guidance from Poison Control immediately. Help from Poison Control is available at www.poison.org and by phone at 1-800-222-1222. Both options are free, confidential, and available 24 hours a day.

Written by:
Maris Copeland, PharmD Candidate Class of 2023
Pharmacy Student, VCU School of Pharmacy

Medically reviewed by:
Kelly Johnson-Arbor, MD
Medical Toxicologist

Poisoned?

Call 1-800-222-1222 or

HELP ME online

This Really Happened

Case 1: A 26-year-old woman went to the hospital after taking sixteen capsules of 20 mg omeprazole that had been prescribed to her for abdominal pain. Upon arrival at the hospital, she had a headache and was drowsy and sweaty. Her face was flushed, and her heart rate was abnormally elevated. Doctors ran blood tests, which were normal. Her headache and other symptoms improved over the next six hours, and by the following day  her only remaining symptom was abdominal pain.

Case 2: A 40-year-old man went to the hospital, 20 hours after ingesting twenty 20 mg omeprazole capsules. His initial symptoms included drowsiness, blurred vision, a dry mouth and throbbing headache. At the hospital, his physical examination and blood tests were normal, and his symptoms gradually resolved over the next day. 


For More Information

Omeprazole (Oral Route) (Mayo Clinic)

Omeprazole Tablets (Cleveland Clinic)


References

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Poisoned?

Call 1-800-222-1222 or

HELP ME online

This Really Happened

Case 1: A 26-year-old woman went to the hospital after taking sixteen capsules of 20 mg omeprazole that had been prescribed to her for abdominal pain. Upon arrival at the hospital, she had a headache and was drowsy and sweaty. Her face was flushed, and her heart rate was abnormally elevated. Doctors ran blood tests, which were normal. Her headache and other symptoms improved over the next six hours, and by the following day  her only remaining symptom was abdominal pain.

Case 2: A 40-year-old man went to the hospital, 20 hours after ingesting twenty 20 mg omeprazole capsules. His initial symptoms included drowsiness, blurred vision, a dry mouth and throbbing headache. At the hospital, his physical examination and blood tests were normal, and his symptoms gradually resolved over the next day.