How Long Does It Take for Omeprazole to Work?
Key takeaways:
Omeprazole (Prilosec) is a proton pump inhibitor. It reduces stomach acid to treat conditions like heartburn, gastroesophageal reflux disease (GERD), and gastrointestinal ulcers.
How long it takes for omeprazole to work can vary. You may feel relief within the first day of starting the medication. But it can take up to 4 days for omeprazole to reach its maximum effects.
Taking omeprazole daily is the most effective way to take it. As-needed doses don’t work as well, so make sure you take it consistently unless a healthcare professional instructs you otherwise.
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Table of contents
Omeprazole (Prilosec) is a medication that treats conditions caused by too much stomach acid. Over-the-counter (OTC) omeprazole is approved to treat heartburn. Prescription-only omeprazole is approved to treat several conditions, including gastroesophageal reflux disease (GERD), intestinal and gastric ulcers, and erosive esophagitis.
Heartburn, GERD, or similar conditions are uncomfortable, which means you may want speedy relief from your symptoms. But omeprazole doesn’t work right away, so it’s a good idea to know what to expect if you're just starting this medication. Below, we’ll cover how long it takes for omeprazole to work and factors that can affect its onset.
How long does it take for omeprazole to start working?
How long it takes for omeprazole to start working, and when it reaches its full effects, are different questions. We’ll cover both below.
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Initial effects
Omeprazole starts to reduce stomach acid within one hour of taking it. You’re likely to feel some relief within the first day of taking it. But full relief is unlikely for a few days.
Full effects
It may take up to 4 days before omeprazole reaches its full effects.
Omeprazole works by reducing stomach acid (more on this below). It starts to reduce stomach acid within an hour and reduces acid by about 50% within 24 hours. But it can take a few days for omeprazole to suppress enough stomach acid to effectively treat conditions like GERD and stomach ulcers.
Keep in mind that even though omeprazole achieves its maximum effect within a few days, it takes longer for your condition to fully heal. For example, omeprazole treatment for GERD is typically 4 weeks.
How does omeprazole work?
Proton pump inhibitors (PPIs) like omeprazole work by blocking enzymes (proteins) in the stomach called proton pumps. Normally, proton pumps produce stomach acid, which helps break down food and absorb nutrients. But too much acid can cause issues like heartburn and GERD. By blocking the protein pump, omeprazole relieves symptoms of these conditions. This includes a burning sensation in the throat and chest, nausea, and difficulty swallowing.
Omeprazole can improve symptoms and heal your condition. But low stomach acid levels need to be maintained over an extended period of time.
Proton pumps are constantly being “recycled.” That means new ones form and old ones stop working. This is a major reason why it takes several days for omeprazole to reach its full effects after you start taking it. This is also why you need to take consistent, daily omeprazole doses to treat conditions like GERD. Taking it as needed won’t allow it to reach its full potential.
What factors affect how long it takes omeprazole to work?
You can’t speed up how quickly omeprazole starts working. But you can help it reach its maximum potential by taking it consistently. As mentioned above, skipping doses or only taking it as needed doesn’t reduce acid levels as much as taking it daily. This can lead to less symptom improvement and slow down healing of your condition.
While waiting for omeprazole to work, you may be able to take it with other heartburn medications, such as antacids. Antacids provide quick heartburn relief, usually within minutes of taking them. But their effects don’t last as long.
Stop the burning. Real people share what it’s like to take omeprazole for heartburn.
Omeprazole side effects: Read what experts say about omeprazole side effects — from headaches to stomach pain — and how to manage them.
Omeprazole tips: GoodRx pharmacists cover a few things you should know about omeprazole.
Talk with a healthcare professional about whether taking an antacid with omeprazole is a good idea for you. Examples include Tums (calcium carbonate) and Rolaids (calcium carbonate / magnesium hydroxide).
What to expect when starting omeprazole
Omeprazole is generally well tolerated. But it can cause mild side effects. These effects may improve over time as your body adjusts to the medication. Examples include:
Headache
Stomach pain
Nausea and vomiting
Diarrhea
Passing gas
If these symptoms continue or worsen, tell your prescriber. Taking omeprazole long term or at high doses increases your risks of more serious side effects like low magnesium levels, broken bones, and lung infections. If side effects seem severe, call 911 immediately.
How long do you need to take omeprazole?
How long you need to take omeprazole depends on what you’re treating. For example, heartburn may only require 2 weeks of treatment. Other conditions may require months or years of treatment.
Indication | Typical length of use |
|---|---|
Heartburn | |
GERD | Up to 4 weeks |
Stomach or intestinal ulcers | 4-8 weeks (depending on the type of ulcer) |
Helicobacter pylori infection | 10-14 days |
Erosive esophagitis | 4-8 weeks, and possibly longer |
May require years of treatment |
It’s important to take omeprazole for the full length of time your prescriber recommends. But if you’re having side effects, let them know. They can determine whether you need a lower dose or a different medication altogether.
If the symptoms of your condition continue, you may need a higher omeprazole dose. Or you may need a combination of more than one acid-reducing medication.
If you’ve been self-treating with omeprazole for more than 2 weeks, or you're taking it and not sure why, seek advice from a healthcare professional. They may recommend stopping omeprazole.
If your prescriber recommends stopping omeprazole, follow their instructions for how to do it. This may involve switching to another acid-reducing medication, such as histamine-2 antagonists (H2 blockers) like famotidine (Pepcid Complete, Pepcid AC).
Frequently asked questions
Omeprazole can interact with other medications. This can affect how well these medications work or increase the chance of side effects.
For example, omeprazole may increase the levels of warfarin (Coumadin, Jantoven), a blood thinner, and citalopram (Celexa), an antidepressant. This can lead to an higher risk of side effects, such as bleeding with warfarin and heart problems or serotonin syndrome with citalopram.
Give your healthcare team a list of the medications and supplements you take before starting omeprazole. They can help you check for drug interactions.
What foods should you avoid while taking omeprazole?
You may want to avoid foods and drinks that can worsen heartburn, GERD, and other conditions caused by high stomach acid. This includes fatty, spicy, or acidic foods (such as oranges and tomatoes). Alcohol and caffeine can also trigger reflux and heartburn.
Additionally, eating at least 3 hours before bedtime can give your stomach time to empty before you lay flat, making acid movement to your esophagus less likely.
If you’re taking omeprazole and your symptoms haven’t improved within a few days, contact a healthcare professional. They might want to confirm that you’re taking it correctly. Omeprazole is usually taken once daily, about 30 minutes before your first meal of the day.
If you’re taking omeprazole correctly and it’s still not working, your healthcare professional may increase your dose, switch you to another PPI, or add another medication to your regimen such as an H2 blocker.
The bottom line
Omeprazole (Prilosec) is a medication that treats conditions like heartburn, gastroesophageal reflux disease (GERD), and gastrointestinal ulcers. It works by reducing stomach acid.
How long omeprazole takes to work may vary. It can start reducing stomach acid within an hour, and you may feel some symptom relief within 24 hours of your first dose. But it takes up to 4 days for omeprazole to reach its maximum effect. Some conditions require several weeks of treatment with omeprazole to effectively heal.
Make sure to take omeprazole daily unless instructed otherwise by a healthcare professional. This helps it reach its maximal effects.
If omeprazole doesn’t improve your symptoms within a few days, or if you’ve been using omeprazole for more than a couple of weeks without consulting a healthcare professional, reach out to your healthcare team. They can let you know whether you should continue taking it.
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References
Ahmed, A., et al. (2023). Proton pump inhibitors (PPI). StatPearls.
Chartwell RX. (2023). Omeprazole- omeprazole capsule, delayed release [package insert].
Graham, D. Y., et al. (2018). Interchangeable use of proton pump inhibitors based on relative potency. Clinical Gastroenterology and Hepatology.
Kinoshita, Y., et al (2018). Advantages and disadvantages of long-term proton pump inhibitor use. Journal of Neurogastroenterology and Motility.
Shin, J. M., et al. (2008). Pharmacology of proton pump inhibitors. Current Gastroenterology Reports.
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