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What is lansoprazole (Prevacid)?

Lansoprazole is a proton pump inhibitor (PPI). It reduces the amount of acid produced in your stomach to ease symptoms of a range of conditions.

Lansoprazole is available as a generic medication, but it is the active ingredient in Prevacid, a brand-name drug.

Lansoprazole comes in two oral forms:

  1. Orally disintegrating tablet (15mg, 30mg)

  2. Capsule (15mg, 30mg)

Your pharmacist can also provide lansoprazole as an oral liquid solution (3mg/ml)¹. This may be more suitable for children or people with feeding tubes.

The drug is available over the counter as a 24-hour delayed-release capsule (15mg), both as a generic medication and Prevacid 24HR.

Your doctor can give you a prescription for lansoprazole in different strengths.

What is lansoprazole used to treat?

Lansoprazole is used to treat a range of conditions caused by too much stomach acid. It works by reducing the amount of acid produced in your stomach.

The drug can ease symptoms² of:

  • Gastroesophageal reflux disease (GERD)

  • Erosive esophagitis (inflamed esophagus)

  • Stomach ulcer

  • Stomach ulcers caused by nonsteroidal anti-inflammatory drugs (NSAIDs)

  • Duodenal ulcers (ulcers that occur in the first part of your small intestine) with or without a Helicobacter pylori (H. pylori) infection

  • Zollinger-Ellison syndrome and other conditions caused by the stomach producing too much acid

You can take over-the-counter lansoprazole to ease frequent heartburn that occurs on two or more days a week. Note that this dosage and format are not designed to provide immediate relief for heartburn.

How do you take lansoprazole?

Your dosage and medication schedule will depend on:

  • Your age

  • Your reaction to the first dose

  • Your medical condition

  • Other medical conditions you have

  • The severity of your condition

Your doctor will typically prescribe the lowest effective dose.

Follow your doctor’s advice and read the usage instructions that come with your medicine. If you don’t understand these instructions, ask your doctor or pharmacist for help.

How to take lansoprazole capsules

Swallow the capsules whole with a glass of water. Don’t crush them or break them apart. Don’t chew the capsule.

If you struggle to swallow the capsules, break them open and sprinkle the medication on a tablespoon of applesauce, yogurt, cottage cheese, or something similar. You should not chew the mixture; swallow it straight away.

You can also pour the contents of the capsule into 60ml of juice. Mix it and swallow it straight away. Ensure you have taken all the medication by rinsing the glass with additional juice and drinking it.

How to take lansoprazole orally disintegrating tablets

Put an orally disintegrating tablet on your tongue and wait one minute for it to dissolve. Swallow it with or without water.

Do not crush, chew, or break the orally disintegrating tablet.

You can also take an orally disintegrating tablet using an oral syringe. This may help if you have difficulty swallowing an orally disintegrating tablet.

Put the tablet in the syringe and draw up 4ml of water for a 15mg tablet or 10ml for a 30mg tablet. Shake the syringe and squirt the liquid into your mouth straight away. Next, draw 2ml of water into the syringe, shake, and squirt the liquid into your mouth. You should do this straight away; don’t wait for more than 15 minutes after dissolving the tablet into the water.

How to take lansoprazole oral liquid solution

Shake the solution well before use.

Measure out the liquid using a medical measuring spoon — not one from your kitchen. You can ask your pharmacist to provide one.

The drug is best taken in the morning on an empty stomach.

Typical adult dosage

Heartburn (over-the-counter lansoprazole): 15mg once daily for 14 days³.

Stomach ulcers: 30mg daily for up to eight weeks.

Duodenal ulcer: 15mg once daily for four weeks (short-term use). 15mg once daily (maintenance).

NSAID-associated stomach ulcer: Start with 30mg once daily for eight weeks. For prevention, take 15mg once daily for up to 12 weeks.

Erosive esophagitis: 30mg once daily for up to eight weeks (short-term treatment). 15mg once daily (maintenance).

Gastroesophageal reflux disease (GERD): 15mg once daily for up to eight weeks.

Seeing results

You may start to notice your heartburn easing within one day² of taking lansoprazole. However, it could take up to four days to notice the benefits.

Worsening symptoms of stomach problems and heartburn could indicate a more serious health condition, like stomach cancer. Speak to your doctor if you don’t notice any improvements or your symptoms return after treatment.

Potential risks of lansoprazole

Lansoprazole carries potential risks and may cause side effects.

Common side effects

Common adverse effects of lansoprazole⁴ include:

  • Diarrhea

  • Stomach pain

  • Nausea

  • Constipation

  • Headache

Speak to your doctor if these common side effects continue or worsen.

Serious side effects

Serious side effects of lansoprazole can include the following:

Vitamin B-12 deficiency

Taking this drug for longer than three years can affect your stomach’s ability to absorb vitamin B-12. Vitamin B-12 deficiency symptoms can include:

  • Pale skin

  • Difficulty with balance and coordination

  • Dizziness

  • Weakness

  • Tiredness

  • A tingling sensation in your hands or feet

Low magnesium levels

Taking this medication for three months or longer may lower your magnesium levels. Symptoms can include:

  • Tremors

  • Muscle cramps

  • Irregular heart rate

Diarrhea from C. diff infection

Symptoms may include:

  • Stomach pain

  • Fever

  • Watery diarrhea

Tubulointerstitial nephritis

Tubulointerstitial nephritis is a kidney problem where tissue in the kidney becomes inflamed. This can occur at any time while taking lansoprazole. Symptoms include:

  • Nausea

  • Fever

  • Changes in urination

  • Blood in the urine

Bone fractures

Taking multiple daily doses or high daily doses of PPIs like lansoprazole carries the risk of bone fractures to the hip, spine, and wrist. The risk is also greater if you take PPIs for a long period (one year or more).

Lupus erythematosus

Lansoprazole may cause some types of lupus erythematosus, an autoimmune condition. Taking this medication may also worsen pre-existing lupus. Symptoms include:

  • A rash on your arms or cheeks that gets worse in the sun

  • Joint pain that worsens

Fundic gland polyps

Taking lansoprazole for a long period can lead to fundic gland polyps. These have a low risk ⁵ of causing cancer, but your doctor may recommend you stop taking lansoprazole.

Discuss any potential side effects with a doctor who knows your medical history before taking this medication. Seek medical help if you experience any of the symptoms of serious side effects listed above.

Long-term use of lansoprazole

The risk of serious side effects increases with long-term use of lansoprazole. Your doctor may monitor you closely if you need to take lansoprazole for a long period of time.

Take lansoprazole for the shortest period and at the lowest possible dose to manage your symptoms. This could reduce your risk of developing serious adverse effects, like bone fractures.

Missed doses

Take your missed dose as soon as you remember. If it’s nearly time to take your next dose, skip the missed dose and resume your normal dosing schedule. Don’t take two doses of lansoprazole at once as this could have harmful effects.


If you think you or someone else has taken too much lansoprazole, seek emergency medical care immediately.

Call 911 if someone has a seizure or has collapsed, they can’t be woken up, or they are having trouble breathing.

Allergy information

Lansoprazole may cause a severe allergic reaction in some people. Symptoms can include:

  • Rash

  • Tightness in your throat

  • Facial swelling

  • Trouble breathing

If you develop these symptoms, call 911 immediately or go to the nearest hospital.

What to discuss with your doctor before taking lansoprazole

Before taking lansoprazole, you must tell your doctor or pharmacist what prescription and non-prescription medications, vitamins, nutritional supplements, and herbal products you are currently taking or plan to take. You must advise them if you are taking St John’s Wort.

Your doctor must be aware if you are taking rilpivirine (Edurant or Juluca) or sucralfate (Carafate).

Tell your doctor about any other health conditions you have, including low magnesium levels, osteoporosis, phenylketonuria, or an autoimmune disease.

Your doctor must know if you are pregnant or breastfeeding before you take lansoprazole. If you plan to become pregnant while taking this medication, let your doctor know.

Stopping lansoprazole

Keep taking lansoprazole even if you start to feel better. Speak to your doctor before stopping your medication.

If you notice your symptoms worsening, seek medical advice straight away.

Lansoprazole and pregnancy

Lansoprazole is not thought to harm a fetus when taken during pregnancy⁴, but not enough is known about the drug’s effects to determine whether or not it’s safe for pregnant women.

Data from animal studies have shown the drug may affect fetal bone growth and development.

If you find out you are pregnant while taking the drug, speak to your doctor immediately.

Taking lansoprazole while breastfeeding

It is not known if lansoprazole passes into human milk and what effect it may have.

Ensure your doctor or pharmacist is aware you are breastfeeding before you take lansoprazole.

Interactions with other drugs

Lansoprazole may interact with certain medicines or supplements, affecting how either drug works or causing adverse effects.

Tell your doctor and pharmacist if you are taking other medications or supplements, including prescription and over-the-counter medications, vitamins, and natural remedies.

You should not take lansoprazole with rilpivirine (Edurant or Juluca). If you need to take rilpivirine, your doctor may recommend an alternative drug to lansoprazole.

Lansoprazole may also interact with these drugs:

  • Acalabrutinib (Calquence)

  • Amphetamine (Adzenys XR-ODT, Dyanavel XR, or Evekeo)

  • Atazanavir (Reyataz)

  • Atorvastatin (Lipitor)

  • Benzphetamine

  • Bosutinib (Bosulif)

  • Capecitabine (Xeloda)

  • Cilostazol (Pletal)

  • Citalopram (Celexa)

  • Clopidogrel (Plavix)

  • Dacomitinib (Vizimpro)

  • Dasatinib (Sprycel)

  • Delavirdine (Rescriptor)

  • Dextroamphetamine (Dexedrine)

  • Dicumarol

  • Erlotinib (Tarceva)

  • Escitalopram (Lexapro)

  • Eslicarbazepine acetate (Aptiom)

  • Ketoconazole (Nizoral)

  • Gefitinib (Iressa)

  • Ledipasvir (Harvoni)

  • Levothyroxine (Levoxyl, Levo-T, Unithroid, and others)

  • Lisdexamfetamine (Vyvanse)

  • Methamphetamine (Desoxyn)

  • Mycophenolate (CellCept)

  • Nelfinavir (Viracept)

  • Neratinib (Nerlynx)

  • Nilotinib (Tasigna)

  • Octreotide (Mycapssa)

  • Pazopanib (Votrient)

  • Pexidartinib (Turalio)

  • Saquinavir (Invirase)

  • Selpercatinib (Retevmo)

  • Sunitinib (Sutent)

  • Secretin human (Chirhostim)

  • Tacrolimus (Prograf, Envarsus XR, or Astagraf XL)

  • Velpatasvir (Epclusa)

  • Vismodegib (Erivedge)

  • Voriconazole (Vfend)

  • Warfarin (Coumadin or Jantoven)

Your doctor may recommend taking lansoprazole with these drugs if doing so is essential, but they may prescribe a modified regimen.

This list is not exhaustive, so you must tell your doctor about all medications you are currently taking.

Drug approval history

1995: Lansoprazole, marketed under the brand name Prevacid, is approved by the Federal Drug Administration (the FDA) as a delayed-release capsule.

2001: The FDA approves lansoprazole as an oral suspension.

2002: The FDA approves lansoprazole as an orally disintegrating tablet.

2009: Lansoprazole is approved by the FDA as a 24-hour delayed-release capsule (Prevacid 24HR).

Tips and advice for taking lansoprazole

Follow this advice to help you take lansoprazole safely and effectively:

  • Over-the-coun­ter lansoprazole (15mg) should only be used for frequent heartburn (twice or more per week).

  • Tell your doctor or pharmacist about any other medications, prescription or over-the-counter, that you’re currently taking or plan to start taking. They may interact with lansoprazole.

  • Try using an oral syringe and water if you have trouble swallowing lansoprazole as an orally disintegrating tablet.

  • If you have difficulty swallowing lansoprazole as a capsule, you can open it up and sprinkle its contents on a food substance like apple sauce or cottage cheese. Remember to swallow the mixture straight away; don’t chew it. Alternatively, you can mix the capsule’s contents with juice.

  • Don’t stop taking this medication without speaking to your doctor first.

  • If your symptoms worsen or don’t go away, speak to your doctor.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.


Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.

However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.

It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.

Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.