Lansoprazole

Pronunciation: lan-SOAP-ra-zole.

Generic name: lansoprazole
Drug class: Proton-pump inhibitor (PPI)
Form: Delayed-release (gastro-resistant) capsule or orally disintegrating tablet, depending on product and country
Route: Oral
Legal status: Prescription and, in some markets, non-prescription pathways exist; this page does not assume OTC status for any specific country.

Availability and supply rules vary by country

Trade names by country: United States · Canada

What lansoprazole is and how it works

Lansoprazole is a proton-pump inhibitor that reduces stomach acid production. (1) (2)

It is used for several acid-related conditions. The exact approved use, product, and duration depend on the country and specific product; this page cannot give a single universal dosing plan.

Mechanism of action: how lansoprazole works

Lansoprazole is a proton-pump inhibitor that irreversibly binds the H+/K+-ATPase enzyme system in gastric parietal cells, suppressing stomach acid secretion. (1)

What lansoprazole is used for

Gastro-oesophageal reflux and related conditions

Used for conditions related to excess stomach acid, including gastro-oesophageal reflux disease, per US and UK prescription product information. The exact indication wording and duration are product- and country-specific. (1) (2)

Helicobacter pylori eradication (combination treatment)

Used as one part of a prescribed combination regimen with antibiotics to eradicate H. pylori infection, per US and UK product information. This is always a prescriber-directed combination, never a self-selected regimen. (1) (2)

Before taking lansoprazole

Do not take / not appropriate for

Do not take lansoprazole if you have a known hypersensitivity to lansoprazole or to any other ingredient of the product. Hypersensitivity reactions have included anaphylaxis, anaphylactic shock, angioedema, bronchospasm, acute tubulointerstitial nephritis and urticaria. (all countries) (1)
Do not take lansoprazole, or any other proton pump inhibitor, together with a rilpivirine-containing HIV medicine. This combination is contraindicated because the proton pump inhibitor lowers rilpivirine levels and can make the HIV treatment fail. (all countries) (1)
If lansoprazole has been prescribed as part of a combination course with clarithromycin and amoxicillin for Helicobacter pylori, the contraindications for those antibiotics apply as well — for example, do not take the amoxicillin component if you are allergic to penicillins. (all countries)

Tell your clinician about

New, persistent, or alarm symptoms such as difficulty swallowing, unexplained weight loss, vomiting blood, or black stools, since lansoprazole can mask symptoms of a more serious underlying condition.
Liver disease.
Low magnesium levels, or any medicine that can lower magnesium.
Osteoporosis or fracture risk.
Every other medicine you take.
Pregnancy or breastfeeding.

(1) (2)

How to take lansoprazole

Take exactly as directed on the product label or by your prescriber.
Follow the specific instructions for your exact formulation (gastro-resistant capsule or orally disintegrating tablet); these are not interchangeable.
If part of an H. pylori eradication regimen, take the complete combination exactly as prescribed.
Do not use for longer than directed, and seek medical assessment for symptoms that persist, recur, or are accompanied by alarm symptoms, rather than continuing to self-treat.

(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3)

Missed dose

Follow the product instructions for missed doses, or ask your prescriber or pharmacist. Do not take a double dose to make up for a missed one.

Overdose

Contact your prescriber, pharmacist, or a poison-control/emergency service if an overdose is suspected.

Side effects

Lansoprazole is generally well tolerated, but longer-term use is associated with some specific risks that need monitoring.

Headache, diarrhoea, nausea, or stomach pain

What to notice: Commonly reported effects.

What to do: Tell your prescriber or pharmacist if severe or persistent. (1)

Nausea and vomiting

Incidence: Common

Headache

Incidence: Common

Signs of low magnesium

What to notice: Muscle spasms, irregular heartbeat, or seizures, particularly with long-term use.

What to do: Contact your prescriber promptly; blood testing may be needed. (1)

Alarm digestive symptoms

What to notice: Difficulty swallowing, unexplained weight loss, vomiting blood, or black stools.

What to do: Seek prompt medical assessment; do not simply continue or increase self-treatment, since these symptoms need investigation and lansoprazole can mask an underlying serious condition. (2)

Serious warnings

Severe allergic or skin reaction — emergency

Symptoms: Swelling of the face, lips, or throat, difficulty breathing, or a severe skin reaction.

Action: Seek emergency medical help immediately. (1)

Masking of a more serious underlying condition — urgent

Symptoms: Persistent or alarm digestive symptoms that seem to improve with lansoprazole.

Action: Seek medical assessment rather than assuming symptom relief means there is no underlying condition needing investigation. (2)

Interactions

Medicine or test	Effect	Action
Medicines requiring stomach acid for absorption (e.g. certain antifungals, some HIV medicines)	Reduced stomach acid from lansoprazole can lower the absorption of some other medicines.	Tell your prescriber and pharmacist about all other medicines you take. (2)

Pregnancy, breastfeeding, kidney/liver function, age

Long-term use

Longer-term PPI use is associated with risks including low magnesium, certain infections, and fracture risk; use the lowest effective dose for the shortest necessary time and have ongoing need reviewed periodically. (2)

Liver impairment

Liver disease may require dose adjustment; discuss with your prescriber. (1)

Pregnancy and breastfeeding

Discuss the balance of benefits and risks with your prescriber before starting, stopping, or continuing lansoprazole in pregnancy or while breastfeeding. (2)

Monitoring

Before starting

Confirm the diagnosis and rule out alarm symptoms needing separate investigation.
Confirm the exact product and formulation.

During treatment

Reassess ongoing need periodically, especially for long-term use.
Monitor magnesium levels with prolonged treatment if clinically indicated.
Investigate rather than continue self-treating if alarm symptoms develop.

(2)

Storage

Store as directed on the product label, out of reach of children.

Study the drug class: Proton pump inhibitors

Professional information

Clinician-facing context only. Use the current local product information for exact indication, dosing, and duration.

United States / United Kingdom

Indication: Acid-related conditions and H. pylori eradication (combination therapy)

Dose summary: No universal dose is displayed; dosing is formulation-, indication-, and country-specific. Use the current local product information.

Renal context: Not detailed in the sources reviewed for this dossier. (1) (2)

Mechanism of action

Hepatic guidance

May require dose adjustment in hepatic impairment; use current local product information.

Overdose note

Not detailed in the sources reviewed for this dossier; manage suspected overdose supportively per local guidance. (1)

Frequently asked questions

What is lansoprazole used for?

lansoprazole is prescribed for approved indications. Always follow your healthcare provider's guidance.

What are the side effects of lansoprazole?

Common side effects may include gastrointestinal symptoms and headache. Serious side effects require immediate medical attention.

Can I take lansoprazole with other medications?

Always inform your healthcare provider about all medications you are taking, including over-the-counter products and supplements.

What is the mechanism of action of lansoprazole?