Prilosec (omeprazole) is taken once daily, at least one hour before a meal. That’s the standard dose for most conditions, whether you’re using the over-the-counter version or a prescription. But how long you keep taking it, and whether you can repeat courses, depends on why you’re using it.
Standard Dosing: Once a Day Before Eating
The recommended adult dose is 20 mg once daily, taken before eating. Timing matters here: Prilosec works by shutting down acid pumps in your stomach lining, and those pumps are most active when you’re about to eat. Taking it at least one hour before a meal gives the medication time to absorb and start blocking acid production before food triggers it. Most people take it in the morning before breakfast, though the key is consistency.
Prilosec comes as a delayed-release capsule, meaning it has a coating designed to survive your stomach acid and dissolve in your intestine. Crushing or chewing it defeats that design and can reduce how well it works.
OTC Prilosec: The 14-Day Rule
If you’re buying Prilosec over the counter for frequent heartburn, the labeled course is one pill daily for 14 days. This isn’t a take-as-needed medication like antacids. You take it every day for the full two weeks, even if symptoms improve sooner, because the drug needs time to fully suppress acid production and let irritated tissue heal.
After completing a 14-day course, you should wait at least four months before starting another one. The FDA labeling is specific: do not take it for more than 14 days or more often than every four months unless a doctor directs otherwise. The OTC packages sold in 28-count and 42-count boxes contain two or three separate 14-day courses, each meant to be spaced four months apart.
If you find yourself needing Prilosec more frequently than every four months, that’s a signal to talk to a doctor. You may have a condition that benefits from a different treatment plan or a longer prescription course.
Prescription Prilosec: Longer Courses
When prescribed by a doctor, the duration and sometimes the dose change based on the condition being treated.
- GERD (acid reflux disease): 20 mg once daily. A typical course runs 4 to 8 weeks, though your doctor may extend treatment beyond 8 weeks for persistent or severe cases.
- Erosive esophagitis: 20 mg once daily for 4 to 8 weeks. This condition involves visible damage to the esophagus from stomach acid, so the full course is important for tissue healing.
- Gastric ulcers: 40 mg once daily for 4 to 8 weeks. The higher dose reflects the more aggressive acid suppression needed for ulcer healing.
- H. pylori infection: This is the one situation where Prilosec may be taken twice daily. The standard triple-therapy regimen uses 20 mg twice a day alongside two antibiotics for 10 days. If an active ulcer is present, an additional 18 days of once-daily Prilosec follows to finish healing.
The frequency stays at once daily for nearly every use. Twice-daily dosing is reserved for specific infection-treatment protocols and occasionally for conditions where a doctor determines standard dosing isn’t enough.
Why Timing and Duration Matter
Prilosec doesn’t neutralize acid that’s already in your stomach the way an antacid does. It blocks the enzyme that produces acid in the first place, and each dose deactivates only the acid pumps that are active at that moment. New pumps regenerate over time, which is why you need to take it daily for the drug to build up its full effect. Most people notice meaningful symptom relief within a few days, but maximum acid suppression typically takes several days of consistent use.
This also explains why stopping abruptly after long-term use can cause a temporary rebound effect, where your stomach produces more acid than it did before you started. If you’ve been on Prilosec for weeks or months, tapering off gradually (such as switching to every other day for a week or two) can help avoid that uncomfortable surge.
If You Miss a Dose
Take it as soon as you remember, as long as it’s still well before your next scheduled dose. If it’s close to the time you’d normally take tomorrow’s pill, skip the missed one and resume your regular schedule. Don’t double up to compensate. Missing a single dose won’t cause harm, but consistency over the full course gives you the best results.