Prilosec (omeprazole) works best when taken once a day, in the morning, before your first meal. The over-the-counter version comes as a 20 mg delayed-release tablet designed for a 14-day course, one pill every 24 hours. Getting the timing and duration right makes a real difference in how well it controls your symptoms.
When to Take It
Take your Prilosec capsule or delayed-release tablet before eating, preferably in the morning before breakfast. The drug needs time to absorb and reach the acid-producing pumps in your stomach lining, and those pumps are most active when you eat. Taking it before a meal ensures the medication is working right when your stomach ramps up acid production.
If you’re using the powder form mixed into a liquid, take it on an empty stomach at least one hour before eating. The regular tablet form is more flexible and can be taken with or without food, but the capsules and delayed-release versions should go before meals for the best results.
The 14-Day Treatment Cycle
Prilosec OTC is not a take-as-needed medication. You take one pill every 24 hours, every day, for a full 14 days, even if your symptoms improve before that. The drug builds up its effect over the course of treatment, so stopping early can leave you with incomplete relief.
After finishing a 14-day course, you need to wait at least four months before starting another round. You should not exceed three courses per year without a doctor’s guidance. If your symptoms return before four months have passed, or if you find yourself needing Prilosec more frequently, that’s a sign something else may be going on and worth getting checked out.
Prescription omeprazole follows different rules. Your doctor may prescribe it at higher doses or for longer durations depending on the condition being treated, such as ulcers or more severe reflux disease.
If You Have Trouble Swallowing Capsules
You don’t have to swallow the capsule whole. Place one tablespoon of applesauce in a bowl, open the capsule, and empty the small pellets directly onto the applesauce. Mix them in, then swallow the mixture right away with a glass of cool water. The key rule: do not chew or crush the pellets. They have a special coating that protects the medication from stomach acid so it can absorb properly. Crushing them destroys that coating and can make the drug less effective or irritate your stomach.
Don’t save the applesauce mixture for later. Prepare it and take it immediately.
What to Do If You Miss a Dose
If you forget a dose, take it as soon as you remember, as long as it’s not close to the time of your next scheduled dose. In that case, skip the missed one and continue your normal schedule. Never double up to make up for a missed pill.
Medications That Don’t Mix Well
The most important drug interaction to know about involves the blood thinner clopidogrel (Plavix). Omeprazole interferes with the liver enzyme that converts clopidogrel into its active form, which can reduce the blood thinner’s effectiveness. The FDA revised clopidogrel’s label to specifically warn against combining it with omeprazole. If you take clopidogrel, your doctor will likely recommend a different acid reducer, such as pantoprazole, which has less impact on that enzyme.
Prilosec can also affect how your body absorbs certain other medications. Because it reduces stomach acid so significantly, drugs that need an acidic environment to dissolve properly may not work as well. Let your pharmacist know everything you’re taking before starting a course.
What Happens With Long-Term Use
The OTC version is designed for short bursts, but many people end up on prescription omeprazole for months or years. Extended use changes your stomach’s chemistry enough to affect how you absorb several important nutrients. Research has linked long-term PPI use to lower levels of vitamin B12, vitamin C, calcium, iron, and magnesium.
The mechanism is straightforward for most of these. Your stomach needs acid to break nutrients free from food so your intestines can absorb them. Suppress that acid long enough and certain nutrients start slipping through unabsorbed. Vitamin B12, for example, requires an acidic environment to separate from the proteins it’s bound to in food. Iron absorption, particularly the nonheme iron found in plant-based foods, drops significantly without normal acid levels. Calcium needs the slightly acidic conditions of the upper intestine to dissolve out of food and become available for absorption.
Magnesium depletion is serious enough that the FDA issued a specific warning in 2011 for anyone taking PPIs longer than a year. Low magnesium can cause muscle cramps, irregular heartbeat, and seizures in severe cases. If you’re on long-term omeprazole, periodic blood work to check these levels is a practical step worth discussing with your doctor.
More recently, the FDA flagged hearing loss as a potential signal it’s evaluating in connection with proton pump inhibitors, based on adverse event reports through late 2024. No regulatory action has been taken yet, but it’s something to be aware of if you notice changes in your hearing while on the medication.