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URL of this page: https://medlineplus.gov/druginfo/meds/a601067.html

Lansoprazole, Clarithromycin, and Amoxicillin

pronounced as (lan soe' pra zole) (kla rith' roe mye sin) (a mox i sil' in)

Why is this medication prescribed?

Lansoprazole, clarithromycin, and amoxicillin are used to treat and prevent the return of ulcers (sores in the lining of the stomach or intestine) caused by a certain type of bacteria (H. pylori). Lansoprazole is in a class of medications called proton pump inhibitors. Clarithromycin and amoxicillin are in a class of medications called antibiotics. Lansoprazole works by decreasing the amount of acid made in the stomach. Clarithromycin and amoxicillin work by stopping the growth of the bacteria that may cause ulcers. Antibiotics will not work for colds, flu, or other viral infections.

How should this medicine be used?

Lansoprazole comes as a delayed-release (releases the medication in the intestine to prevent break-down of the medication by stomach acids) capsule, clarithromycin comes as a tablet, and amoxicillin comes as a capsule, all to be taken by mouth. Take these medications before a meal twice a day. To help you take the right number of capsules and tablets at each dose, the medication is packaged in dosing cards. Each dosing card contains all of the medication needed for both daily doses. 

Take the medication exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets and capsules whole; do not split, chew, or crush them.

Take lansoprazole, clarithromycin, and amoxicillin until you finish the prescription, even if you feel better. If you stop taking antibiotics too soon your infection may not be completely treated and the bacteria may become resistant to antibiotics.

If your condition does not improve or gets worse, call your doctor.

Other uses for this medicine

These medications may be prescribed for other uses. Ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking lansoprazole, clarithromycin, and amoxicillin,

  • tell your doctor or pharmacist if you are allergic to this medication, any part of this medication, or any other medications, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.
  • you should know that some medications should not be taken with lansoprazole, clarithromycin, and amoxicillin. Other medications may cause dosing changes or extra monitoring when taken with lansoprazole, clarithromycin, and amoxicillin. Make sure you have discussed any medications you are currently taking or plan to take before starting lansoprazole, clarithromycin, and amoxicillin with your doctor and pharmacist. Before starting, stopping, or changing any medications while taking lansoprazole, clarithromycin, and amoxicillin, please get the advice of your doctor or pharmacist.
  • you should know that the following nonprescription or herbal products may interact with lansoprazole, clarithromycin, and amoxicillin: St. John's wort; iron supplements. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking lansoprazole, clarithromycin, and amoxicillin. Do not start any of these medications while taking lansoprazole, clarithromycin, and amoxicillin without discussing with your healthcare provider.
  • if you are taking sucralfate, take it 30 minutes after you take lansoprazole, clarithromycin, and amoxicillin.
  • you should know that lansoprazole, clarithromycin, and amoxicillin may decrease the effectiveness of hormonal contraceptives (birth control pills, patches, rings, and injections). You will need to use another method of contraception to prevent pregnancy while taking lansoprazole, clarithromycin, and amoxicillin. Talk to your doctor about other ways to prevent pregnancy while you are taking this medication.
  • tell your doctor if you have or have ever had a QT prolongation (a rare heart problem that may cause irregular heartbeat, fainting, or sudden death) or an irregular heartbeat; low levels of potassium or magnesium in your blood; asthma, allergies, hives, hay fever, myasthenia gravis (a disease of muscles and the nerves); or kidney or liver disease.
  • tell your doctor if you are pregnant, plan to become pregnant or are breastfeeding. If you become pregnant while taking these medications, call your doctor.
  • if you are having surgery, including dental surgery, tell your doctor or dentist that you are taking lansoprazole, clarithromycin, and amoxicillin.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do if I forget a dose?

Take the missed dose (one lansoprazole capsule, one clarithromycin tablet, and two amoxicillin capsules) as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Lansoprazole, clarithromycin, and amoxicillin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • stomach pain or cramps
  • nausea, vomiting, diarrhea
  • change in ability to taste food
  • headache
  • dizziness

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

  • blistering or peeling skin
  • rash, hives; swelling of the face, eyes, lips, tongue, arms, or legs; difficulty breathing or swallowing; hoarseness
  • sore throat, fever, chills, and other signs of infection
  • watery or bloody diarrhea with or without stomach pain that occurs during your treatment or for up to 2 months afterward
  • yellow eyes or skin, dark urine; itching, abdominal pain, unexplained bruising or bleeding, or loss of appetite
  • increased heart rate, dizziness, and seizures

Lansoprazole, amoxicillin, and clarithromycin may cause other side effects. Call your doctor if you have any unusual problems while you are taking these medications.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

Keep this medication in the daily packets and storage box it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light and excess heat and moisture (not in the bathroom).

Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location – one that is up and away and out of their sight and reach. https://www.upandaway.org

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website https://goo.gl/c4Rm4p for more information.

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

  • stomach pain, nausea, vomiting, diarrhea
  • decreased urination

What other information should I know?

Keep all appointments with your doctor and the laboratory. Do not let anyone else take your medication. Your prescription is probably not refillable. If you still have symptoms after you finish your prescription, call your doctor.

Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking lansoprazole, clarithromycin, and amoxicillin.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

Brand names

  • Prevpac®

This branded product is no longer on the market. Generic alternatives may be available.

Last Revised - 05/15/2026