Omeprazole: uses, how long to take it and what to watch for

Omeprazole (Prilosec and generics) is a proton pump inhibitor (PPI). According to MedlinePlus, it lowers the amount of acid your stomach makes. Related medicines in the same class include esomeprazole, lansoprazole and pantoprazole, which is sold by prescription only.

Over the counter and prescription. At the pharmacy you can buy it without a prescription as a 20 mg delayed-release tablet for frequent heartburn. By prescription there are capsules in several strengths, and the doctor decides the dose based on what is being treated.

It is not a controlled substance. It is also not a fast-acting antacid: it works by reducing acid production, not by neutralizing the acid already in your stomach.

According to the over-the-counter Drug Facts label and MedlinePlus, omeprazole is used for:

These are the directions on the over-the-counter Drug Facts label for 20 mg omeprazole, similar to Prilosec OTC. For prescription doses, the doctor decides the dose.

• Adults 18 years and older: 1 tablet a day with a glass of water, in the morning before eating, for 14 days in a row.
• Swallow the tablet whole. Do not chew or crush it.
• It is not for immediate relief. The label says it may take 1 to 4 days for full effect, so you may still have symptoms the first few days.
• You may repeat a 14-day course no more than once every 4 months, unless a doctor tells you otherwise.
• Do not use it in people under 18 without asking a doctor.

Taking it before eating matters: per the label, it works best when taken in the morning, before the first meal of the day.

This is the question most worth asking. Over the counter, the limit is 14 days per course and no more than one course every 4 months, unless a doctor says otherwise. If you need more than that, heartburn is no longer something to manage at home on your own.

By prescription, some people need it for weeks or months, for example to heal an ulcer or an irritated esophagus, and some use it longer under supervision. The problem is that many people start it for one symptom and keep taking it for years without anyone checking whether it is still needed, or at what dose.

What the doctor does in a review. She asks about your current symptoms and warning signs, reviews your other medicines, looks for the lowest dose that works and decides with you whether to continue, lower the dose or change the plan. If needed, she can order a lab test, such as vitamin B12, or refer you to a gastroenterologist.

Do not stop suddenly on your own if you have taken it for a long time. Some people notice that heartburn comes back, sometimes stronger, when they stop. It is better to stop with a plan.

According to MedlinePlus and the labels, the most common side effects of omeprazole are usually mild:

FDA-approved labels warn about several risks linked to prolonged daily use or high doses. They are uncommon for most people, but they are the reason a treatment review makes sense:

• Low vitamin B12. Taking an acid-lowering medicine every day for a long time (for example, longer than 3 years) can reduce absorption of vitamin B12. It can cause tiredness, tingling or anemia.
• Low magnesium. Rarely, usually after a year or more of use, and more so if you also take diuretics. It can cause cramps, an irregular heartbeat or seizures.
• Fractures. Use of high doses for a year or longer is associated with hip, wrist and spine fractures, especially in older adults.
• C. difficile diarrhea. These medicines are associated with a higher risk of this intestinal infection. Call your doctor if you have severe diarrhea with watery stools, stomach pain or a fever that does not go away.
• Kidney problems. The label warns of kidney inflammation (interstitial nephritis) that can happen at any point during treatment.
• Lupus and skin reactions. Rarely, a skin or systemic lupus can appear or get worse. Tell the doctor if you get a rash that worsens in the sun, or joint pain.
• Stomach polyps. Use for more than a year is associated with fundic gland polyps, which are usually benign.

None of this means you should stop a medicine you need. It means that taking it for years on autopilot is not ideal.

Tell the doctor and the pharmacist everything you take, including over-the-counter products and natural supplements. The labels describe important interactions with:

• Clopidogrel (Plavix). Omeprazole can reduce its effect. If you take it, do not change anything on your own and ask first.
• Rilpivirine, an HIV medicine, which should not be combined with PPIs.
• Methotrexate, whose levels can rise with PPIs, especially at high doses.
• Warfarin and other blood thinners: closer monitoring may be needed.
• Diuretics, which together with PPIs raise the risk of low magnesium.
• St. John’s wort and rifampin, which can lower the effect of omeprazole.

Omeprazole can also change the absorption of other medicines that need stomach acid. A short list of all your medicines makes the review more useful.

If you are being checked for gastritis or H. pylori bacteria, MedlinePlus explains that some tests can give false results while you take certain medicines, and that you may need to stop them for 2 weeks to a month before the test. Tell the doctor if you take omeprazole before the test, and do not stop it on your own: she will tell you how.

If you are pregnant, could be pregnant or are breastfeeding, ask the doctor before starting or continuing omeprazole. Heartburn is common in pregnancy, and the doctor helps you choose the most appropriate option for you, at the lowest dose possible, and decide whether to try habit changes first.

Not every upper abdominal discomfort is acid. Stomach pain can come from gastritis, an ulcer, the gallbladder, an infection or medicines. Anti-inflammatories such as ibuprofen and naproxen are a common cause of stomach irritation and ulcers, and are sometimes prescribed with a stomach protector.

If you have heartburn and also take anti-inflammatories often, tell the doctor: the most useful change may not be raising the omeprazole, but reviewing the anti-inflammatory.

The changes recommended by the NIDDK are the first step in treating reflux and can allow the dose to come down over time: