Prevacid (Lansoprazole) – Oral

What Is Prevacid?

Prevacid (lansoprazole) is a pill taken by mouth to treat disorders of the digestive system involving stomach acid.

As a proton pump inhibitor (PPI), Prevacid works by attaching to the gastric parietal cells on the outer lining of your stomach and decreasing the amount of gastric (stomach) acid produced by these cells. By decreasing stomach acid, Prevacid relieves symptoms of digestive problems like gastric ulcers, gastroesophageal reflux disease (GERD) or heartburn, and erosive esophagitis associated with GERD.

Prevacid is available as both a prescription product and an over-the-counter (OTC) product. The OTC product (Prevacid 24 HR) is only available as a 15 milligram (mg) dose and is taken once a day. Higher strengths are available as prescription products that your healthcare provider can order for you.

Drug Facts

Generic Name: Lansoprazol

Brand Name: Prevacid, Prevacid SoluTab, Prevacid 24 HR

Drug Availability: Prescription, over the counter

Therapeutic Classification: Proton pump inhibitor

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Oral

Active Ingredient: Lansoprazole

Dosage Form: Capsule, ODT (orally disintegrating tablet)

What Is Prevacid Used For?

Peptic ulcers are sores that develop in some parts of your digestive tract, such as your esophagus, stomach, or small intestine. Prevacid treats many different types of peptic ulcers, including:

Prevacid is also used for treating damage done to the esophagus by gastroesophageal reflux disease (GERD) in adults and children 1 year old and older.

GERD occurs when stomach acid rises from the stomach back up into your esophagus, the tube that carries food from your mouth to your stomach. When this happens often, it causes inflammation and symptoms of heartburn like pain in the throat or chest—all of which characterize erosive esophagitis. Prevacid decreases the amount of stomach acid produced by the body to prevent an excess that can flow back up to your throat and cause heartburn.

Another group of disorders that Prevacid treats is hypersecretory conditions. One example is Zollinger-Ellison syndrome, a rare disease that causes tumors to form in different places along the gastrointestinal tract, such as the stomach, pancreas, or intestine. These tumors secrete an excessive amount of a hormone called gastrin, leading to excess stomach acid. Excess acid causes peptic ulcers.

Prevacid (Lansoprazole) Drug Information: A person's stomach and intestines

Verywell / Zoe Hansen

How to Take Prevacid

Prevacid is available as a capsule and as an orally disintegrating tablet (ODT) called Prevacid SoluTab. It is taken either once or twice a day and should be taken before meals.

Swallow the Prevacid capsules whole. Never crush, cut, or chew them. If you have trouble swallowing capsules whole, open them and empty the contents onto 1 tablespoon of applesauce, pudding, cottage cheese, yogurt, or strained pears and take the dose right away. You can also sprinkle the contents of a capsule into 60 milliliters (about one-fourth cup) of apple juice, orange juice, or tomato juice. Stir and take the dose immediately.

Prevacid ODTs should also not be crushed, cut, or chewed. Place the tablet on the tongue and allow it to disintegrate with or without water. Swallow after the tablet has dissolved, which usually takes a minute or less.

Storing Prevacid

Store Prevacid at room temperature (between 68 and 77 degrees) in its original container, out of reach of children and pets. Avoid storing in an area with heat and moisture, like the bathroom.

If you’re traveling by plane, keep Prevacid in your carry-on luggage so that you aren’t separated from it if your checked baggage goes missing. If you’re traveling by car, take care not to leave your medicine in especially hot or cold temperatures for long periods, like overnight in the car.

Off-Label Uses

There are a number of other conditions for which a healthcare provider may prescribe Prevacid if scientific evidence or clinical experience support these uses.

For example, Prevacid may be used to prevent stress ulcers in patients who are hospitalized and critically ill. Hospitalized patients undergoing major stress and strain on the body can develop ulcers, or open sores, along certain points of the digestive tract.

How Long Does Prevacid Take to Work?

It takes about 2.5 hours for Prevacid to begin decreasing stomach acid production. You may start to feel some relief that quickly, but it may also take one to four weeks for noticeable symptom improvement.

If you’re taking Prevacid for the first time, you will likely start by taking it for a relatively short period–around eight weeks. Your healthcare provider will want to check on your symptoms then and decide whether to extend your treatment or not.

What Are the Side Effects of Prevacid?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at or 800-FDA-1088.

Common Side Effects

Some of the most common side effects that you may experience while taking Prevacid include the following. Note that “most common” in this case means they were experienced by greater than or equal to 1% of participants in clinical trials. None was experienced by more than 4% in trials. These side effects include:

  • Headache
  • Diarrhea
  • Constipation
  • Nausea or vomiting
  • Stomach pain

Severe Side Effects

Potential side effects of Prevacid that may be more serious include:

  • Vitamin B12 deficiency: Stomach acid is needed to absorb vitamin B12 properly, so having less stomach acid can cause low levels, particularly if you have been on Prevacid for more than three years.
  • Hypomagnesemia, or low magnesium levels: This can happen often after a year of treatment. You may or may not have symptoms, which can include dizziness, abnormal heartbeat, shakiness or jitters, and muscle weakness, cramps, or aches.
  • Clostridioides difficile (C. diff) infection: The risk for this infection may be increased particularly in hospitalized patients who are also taking antibiotics in addition to PPIs. Hallmark symptoms are watery diarrhea and abdominal cramping.

Call your healthcare provider immediately if you feel like you are experiencing serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency.

Long-Term Side Effects

In addition to low vitamin B12 and magnesium levels, long-term PPI use may increase the risk for bone fractures in areas like the hip, wrist, or spine. This risk is increased in people who take PPIs multiple times a day for a year or longer.

You may want to ask your healthcare provider about getting your levels checked for vitamin B12 and magnesium and about how you can make sure your bones are staying strong, such as perhaps taking a bone density test.

Report Side Effects

Prevacid may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Prevacid Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (capsules or orally disintegrating tablets):
    • To treat duodenal ulcers:
      • Adults—15 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
      • Children—Use and dose must be determined by your doctor.
    • To treat duodenal ulcers with H. pylori infection:
      • Adults—30 milligrams (mg) before meals 2 or 3 times a day. The dose is usually taken together with amoxicillin or clarithromycin plus amoxicillin. Your doctor may adjust your dose as needed.
      • Children—Use and dose must be determined by your doctor.
    • To treat erosive esophagitis:
      • Adults—30 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
      • Children 12 years of age and older—30 mg once a day before a meal. Your doctor may adjust your dose as needed.
      • Children 1 to 11 years of age and weighing over 30 kg—30 mg once a day before a meal. Your doctor may adjust your dose as needed.
      • Children 1 to 11 years of age and weighing 30 kg or less—15 mg once a day before a meal. Your doctor may adjust your dose as needed.
      • Children younger than 1 year of age—Use and dose must be determined by your doctor.
    • To treat benign gastric ulcers:
      • Adults—30 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
      • Children—Use and dose must be determined by your doctor.
    • To treat gastric ulcers caused by NSAID use:
      • Adults—15 to 30 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
      • Children—Use and dose must be determined by your doctor.
    • To treat gastroesophageal reflux disease (GERD):
      • Adults and children 12 years of age and older—15 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
      • Children 1 to 11 years of age and weighing 30 kg or more—30 mg once a day before a meal. Your doctor may adjust your dose as needed.
      • Children 1 to 11 years of age and weighing 30 kg or less—15 mg once a day before a meal. Your doctor may adjust your dose as needed.
      • Children younger than 1 year of age—Use and dose must be determined by your doctor.
    • To treat Zollinger-Ellison syndrome (ZES):
      • Adults—60 milligrams (mg) once a day before a meal. Your doctor may adjust your dose as needed.
      • Children—Use and dose must be determined by your doctor.



It is unknown whether taking Prevacid while pregnant increases the risk of birth defects or miscarriage. There haven’t been many studies that include pregnant people exposed to PPIs. Still, one was done in 2005 that included 295 pregnancies exposed to different PPIs, including Prevacid, Prilosec (omeprazole), and Protonix (pantoprazole). The rate of birth defects was not significantly higher than the rate in the group that did not take PPIs.

Speak with your healthcare provider about whether the benefit of PPIs may be worth any risk they may pose to a pregnancy. They could be a decent option if lifestyle modifications and other treatment options aren’t sufficient to control symptoms.


Prevacid is present in human breast milk. But the significance of this and whether it negatively affects infants is poorly understood. Again, you will want to discuss with your healthcare provider and decide if Prevacid's benefit outweighs any potential risk to the infant.


Prevacid has been established as safe and effective for children age 1 to 17 years for short-term treatment of GERD and associated erosive esophagitis. It was not found effective for these uses in trials that included neonates and babies younger than 1 year.

Missed Dose

If you forget to take a dose of Prevacid, take it as soon as you remember. However, if you are closer to the next dose, skip the missed dose and wait for your next scheduled dose instead. Do not double up doses to make up for missed ones.

Overdose: What Happens If I Take Too Much Prevacid?

As long as you are taking Prevacid as prescribed, you don’t need to be worried about overdosing. There is little data available regarding the toxicity of lansoprazole at very high doses.

The medicine is not able to be removed by dialysis, a process that can remove some drugs from the body faster than they would work themselves out of your system. Therefore, any treatment for overdosage would most likely be in response to symptoms you are experiencing and keeping you generally well.

Contact your healthcare provider immediately or go to the nearest emergency department if you take too much Prevacid and experience any severe side effects.

What Happens If I Overdose on Prevacid?

If you think you or someone else may have overdosed on Prevacid, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Prevacid, call 911 immediately.


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It is important that your doctor check the progress of you or your child at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood, urine, and other laboratory tests may be needed to check for unwanted effects. If your or your child's condition does not improve, or if it becomes worse, discuss this with your doctor.

Do not take this medicine if you are also using products that contain rilpivirine (Complera®, Edurant®). Using these medicines together may cause unwanted side effects.

Lansoprazole may cause a serious type of allergic reaction when used in patients with conditions treated with antibiotics. Call your doctor right away if you or your child has itching, trouble breathing or swallowing, or any swelling of your hands, face, or mouth.

Check with your doctor right away if you have a change in frequency of urination or amount of urine, blood in the urine, fever, joint pain, loss of appetite, skin rash, swelling of the body or feet and ankles, unusual tiredness or weakness, or unusual weight gain. These could be symptoms of a serious kidney problem called acute tubulointerstitial nephritis.

Taking this medicine for a long time may make it harder for your body to absorb vitamin B12. Tell your doctor if you have concerns about vitamin B12 deficiency.

Serious stomach conditions may occur while taking this medicine alone or together with antibiotics. Check with your doctor immediately if you or your child has stomach cramps, bloated feeling, watery and severe diarrhea which may also be bloody sometimes, fever, nausea or vomiting, or unusual tiredness or weakness.

Lansoprazole may increase your risk of having fractures of the hip, wrist, and spine. This is more likely if you have osteoporosis, if you are 50 years of age and older, if you receive high doses of this medicine, or if you use it for one year or more. Call your doctor right away if you have severe bone pain or are unable to walk or sit normally.

This medicine may cause serious skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, and drug reaction with eosinophilia and systemic symptoms (DRESS). Check with your doctor right away if you have black, tarry stools, blistering, peeling, or loosening of the skin, chest pain, chills, cough, diarrhea, itching, joint or muscle pain, painful or difficult urination, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, or white spots in the mouth or on the lips, swollen glands, unusual bleeding or bruising, or unusual tiredness or weakness.

Cutaneous or systemic lupus erythematosus may occur or get worse in patients receiving a PPI. Call your doctor right away if you have joint pain or a skin rash on your cheeks or arms that gets worse when exposed to the sun.

This medicine may cause hypomagnesemia (low magnesium in the blood). This is more likely to occur if you are taking this medicine for more than one year, or if you are taking this medicine together with digoxin (Lanoxin®) or certain diuretics or "water pills". Check with your doctor right away if you have convulsions (seizures), fast, racing, or uneven heartbeat, muscle spasms (tetany), tremors, or unusual tiredness or weakness.

This medicine may increase your risk for fundic gland polyps (abnormal tissue growth in the upper part of your stomach). This is more likely if you are receiving this medicine for more than 1 year. Talk to your doctor if you have concerns.

Do not stop taking this medicine without first checking with your doctor, or unless told to do so by your doctor.

Before you have any medical tests, tell the medical doctor in charge that you or your child are taking this medicine. The results of some tests may be affected by this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription (eg, atazanavir, nelfinavir, Reyataz®, Viracept®) or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

What Are Reasons I Shouldn't Take Prevacid?

Prevacid may not be the best choice for you if you:

  • Have hypomagnesemia or low magnesium levels in your blood, since Prevacid can lower magnesium levels (Consider asking your healthcare provider about getting this level tested before you start taking lansoprazole.)
  • Have vitamin B12 deficiency since Prevacid can further lower the levels of vitamin B12, also called cyanocobalamin
  • Are taking a medicine that contains rilpivirine, such as Edurant (rilpivirine), Complera (emtricitabine/rilpivirine/tenofovir) or Odefsey (emtricitabine/rilpivirine/tenofovir alafenamide), to treat human immunodeficiency virus (HIV), since Prevacid can lessen how effective these drugs are at treating the virus
  • Have a history of an allergy or serious reaction to Prevacid, such as anaphylaxis, angioedema (swelling under the skin), or exfoliative skin conditions (shedding of the top layers of skin)
  • Have phenylketonuria (PKU) since you need to be aware that Prevacid SoluTabs (ODTs) contains phenylalanine (Each 15 mg SoluTab contains 2.5 mg of phenylalanine and each 30 mg SoluTab contains 5.1 mg of phenylalanine. Consider your other daily sources and discuss this with your healthcare provider.)

What Other Medications Interact With Prevacid?

There are some drugs that can interact with Prevacid and should be monitored by your healthcare provider. These include:

  • Antiretrovirals, especially rilpivirine: Prevacid may lower the effectiveness of these drugs used to treat HIV, which could result in treatment failure. Let your healthcare provider know if you take any medicines containing the drugs rilpivirine, atazanavir, nelfinavir, or saquinavir.
  • Digoxin: Your exposure to digoxin may be increased by Prevacid. A decrease in the dose of digoxin may be necessary.
  • Jantoven (warfarin): Prevacid may strengthen the effects of this blood thinner used to prevent blood clots. This may increase the risk of bleeding. It can also affect results from tests used to evaluate blood clotting.
  • Methotrexate: Prevacid may elevate the concentration of methotrexate in your body, which can lead to toxicity from this drug used to treat autoimmune diseases such as rheumatoid arthritis as well as some types of cancers.
  • Tacrolimus: Your exposure to Astagraf XL (tacrolimus), a drug that prevents organ transplant rejection, may be increased if you take it while you’re also taking Prevacid. Levels of tacrolimus in the blood should be monitored.
  • Acid-dependent drugs: Some drugs, such as iron products, CellCept (mycophenolate mofetil), and Nizoral (ketoconazole), rely on acidity in the stomach for absorption. Since Prevacid lowers the amount of acid, the effectiveness of these drugs may also be lowered.
  • CYP3A4 and CYP219 inducers: Drugs in this category including rifampin, Saint-John's-wort, and ritonavir-containing products may decrease how well lansoprazole works.

What Medications Are Similar to Prevacid?

There are a few other PPI drugs in the same class as lansoprazole.

Like Prevacid, Prilosec (omeprazole) and Nexium (esomeprazole) are both available over the counter. PPIs that require a prescription include Protonix (pantoprazole), Aciphex (rabeprazole), and Dexilant (dexlansoprazole).

Another class of drugs frequently used to treat heartburn symptoms is called H2 blockers, which includes Pepcid AC (famotidine), Tagamet (cimetidine), and Zantac (ranitidine). Be aware that in 2020 the FDA recalled all products containing ranitidine in order to investigate a potential contaminant in the products.

This is not a list of drugs recommended to take with Prevacid; however, sometimes different drug classes may be combined when treatment with one is not sufficient to relieve symptoms. Discuss any questions or concerns with your pharmacist or a healthcare provider.

Frequently Asked Questions

  • What is Prevacid used for?

    Prevacid is used to treat digestive disorders, also known as peptic disorders. These include peptic ulcers, gastroesophageal reflux disease (GERD), and erosive esophagitis associated with GERD (damage to the esophagus). It can also be used for a rare disease called Zollinger-Ellison syndrome, which causes tumors to form in the gastrointestinal tract that lead to peptic ulcers.

  • How does Prevacid work?

    Prevacid is a proton pump inhibitor (PPI). It works by attaching to the outer lining of your stomach and decreasing the amount of stomach acid. Decreased stomach acid results in less discomfort from disorders like gastric ulcers or GERD, more commonly called heartburn.

  • What medicines interact with Prevacid?

    Some drugs may have their effects increased or decreased by Prevacid when taken together. Be sure to let your healthcare provider know if you're taking drugs such as methotrexate, antiretroviral drugs to treat HIV, warfarin, iron products, CellCept (mycophenolate mofetil), and tacrolimus.

How Can I Stay Healthy While Taking Prevacid?

Gastric ulcers are a common issue and can have a variety of causes. The culprit is most often H. pylori infection, a bacterium that can damage your stomach lining, leading to problems like ulcers, inflammation, and pain. On the bright side, H. pylori is treatable with antibiotics and PPIs like Prevacid.

Another leading cause of gastric ulcers is the frequent and long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, Advil or Motrin and Aleve. These drugs may seem benign since many OTC NSAID products are readily available. However, these drugs can disrupt your stomach’s normal ability to maintain efficient digestion.

Symptoms of gastric ulcers include a dull or burning pain in your upper abdomen or your back. Other symptoms may include indigestion, heartburn, nausea, or discomfort with eating. Since ulcers can become serious if left untreated, report symptoms to your healthcare provider.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. DailyMed. Label: Prevacid 24 HR- lansoprazole capsule, delayed release.

  3. Alhazzani W, Alshamsi F, Belley-Cote E, et al. Efficacy and safety of stress ulcer prophylaxis in critically ill patients: a network meta-analysis of randomized trials [published correction appears in Intensive Care Med. 2017 Dec 11;:]. Intensive Care Med. 2018;44(1):1-11. doi:10.1007/s00134-017-5005-8

  4. Diav-Citrin O, Arnon J, Shechtman S, et al. The safety of proton pump inhibitors in pregnancy: a multicentre prospective controlled study. Aliment Pharmacol Ther. 2005;21(3):269-275. doi:10.1111/j.1365-2036.2005.02306.x

  5. Food and Drug Administration. FDA requests removal of all ranitidine products (Zantac) from the market.

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By Sara Hoffman, PharmD
Sara is a clinical pharmacist that believes everyone should understand their medications, and aims to achieve this through her writing.