omeprazole
Brand names: Prilosec, Zegerid, Yosprala, Talicia, Konvomep, Primeguard, Zegerid Reformulated Aug 2006, UlcerGard
Medically Reviewed by Dr. Sarah Chen, PharmD, BCPS
Clinical Pharmacist & Medical Reviewer
Last reviewed: March 19, 2026
Omeprazole (brand name: Prilosec) is a proton pump inhibitor (PPI) available both over-the-counter and by prescription. It reduces stomach acid and is used to treat heartburn, GERD, and stomach ulcers..
Typical Cost
$4–$25/month
Forms
capsule +2
Status
OTC
Generic
Available
Uses & Indications
OTC: Frequent heartburn (2+ days/week). Prescription: GERD, erosive esophagitis, H. pylori eradication (with antibiotics), Zollinger-Ellison syndrome, and NSAID-associated gastric ulcers.
Dosage & Administration
Dosage: How to Take Omeprazole (Omeprazole)
The standard dose of omeprazole (Prilosec) for acid reflux (GERD) is 20 mg once daily for 4–8 weeks. For stomach ulcers caused by H. pylori, the dose is 20 mg twice daily as part of combination therapy. OTC omeprazole is 20 mg once daily for up to 14 days.
Omeprazole Dosage Table
| Indication | Dose | Duration |
|---|---|---|
| GERD / heartburn | 20 mg once daily | 4–8 weeks |
| Erosive esophagitis | 20–40 mg once daily | 4–8 weeks |
| H. pylori eradication | 20 mg twice daily + antibiotics | 10–14 days |
| Zollinger-Ellison syndrome | 60 mg once daily (titrate) | Long-term |
| OTC heartburn | 20 mg once daily | Up to 14 days |
Important Dosage Notes
Take 30–60 minutes before eating for best results. Swallow capsules whole — do not crush or chew.
How It Works
Omeprazole is a prodrug that is activated in the acidic environment of parietal cell secretory canaliculi. It irreversibly inhibits the H+/K+ ATPase (proton pump), blocking the final step of acid secretion.
Side Effects
Serious Side Effects
Common Side Effects
Rare Side Effects
Warnings & Precautions
Long-term use associated with increased risk of C. difficile infection, bone fractures, hypomagnesemia, and vitamin B12 deficiency. May mask symptoms of gastric malignancy.
Contraindications
Contraindicated with rilpivirine-containing products. Hypersensitivity to omeprazole or other PPIs.
Frequently Asked Questions
When is the best time to take omeprazole?
Omeprazole works best when taken 30–60 minutes before your first meal of the day. This allows the drug to be activated and block proton pumps before they are stimulated by eating.
How long can I take omeprazole?
OTC omeprazole is intended for 14-day courses, repeated no more than 3 times per year. Long-term use should be under medical supervision due to risks of B12 deficiency, bone loss, and magnesium deficiency.
Is omeprazole safe to take every day?
Short-term daily use is generally safe. Long-term daily use (months to years) carries risks including hypomagnesemia, bone fractures, and vitamin B12 deficiency. Discuss with your doctor if you need it for more than 8 weeks.
Medical Disclaimer
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