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Tagamet

Generic Name: cimetidine (sye ME ti deen)
Brand Name: Tagamet, Tagamet HB

Medically reviewed: December 15, 2017

Medically reviewed on March 7, 2018

What is Tagamet?

Tagamet is in a group of drugs called histamine receptor antagonists. This medicine works by decreasing the amount of acid your stomach produces.

Tagamet is used to treat and prevent certain types of ulcer, and to treat conditions that cause the stomach to produce too much acid. This medicine is also used to treat gastroesophageal reflux disease (GERD), when stomach acid backs up into the esophagus and causes heartburn.

Tagamet may also be used for other purposes not listed in this medication guide.

Important Information

Use this medication exactly as directed on the label, or as your doctor has prescribed it for you. Do not use more of the medication than recommended. Do not use the medication for longer than recommended.

Avoid taking antacids unless your doctor recommends them for heartburn pain. Follow your doctor's advice about the type of antacid to use and when to use it. You may not be able to take the antacid at the same time you take your dose of Tagamet.

Taking Tagamet may make you more susceptible to virus that can cause pneumonia. This has occurred most often in elderly people and in those with diabetes, a weak immune system, or chronic lung disease. Before using this medicine, tell your doctor if you have any of these conditions.

There are many other drugs that can interact with Tagamet. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Heartburn can be confused with early symptoms of heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, dizziness, pain spreading to the arm or shoulder, sweating, nausea or vomiting, and a general ill feeling.

Before taking this medicine

Heartburn can be confused with early symptoms of heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, dizziness, pain spreading to the arm or shoulder, sweating, nausea or vomiting, and a general ill feeling.

Taking Tagamet may make you more susceptible to virus that causes pneumonia. You may be more likely to develop pneumonia if you have certain health problems.

Ask a doctor or pharmacist if it is safe for you to take Tagamet if you have:

  • diabetes;

  • asthma or a chronic lung disorder;

  • a weak immune system;

  • bone marrow suppression;

  • kidney disease; or

  • liver disease.

Tagamet is in the FDA pregnancy category B. This means that it is not expected to be harmful to an unborn baby. Do not use this medication without telling your doctor if you are pregnant or plan to become pregnant during treatment.

Tagamet passes into breast milk, and may be harmful to a nursing baby. Do not take this medicine without telling your doctor if you are breast-feeding a baby.

Do not give this medicine to a child younger than 16 years old unless your doctor has told you to.

How should I take Tagamet?

Use this medication exactly as directed on the label, or as your doctor has prescribed it for you. Do not use more of the medication than recommended. Do not use the medication for longer than recommended.

Tagamet is usually taken with meals or at bedtime.

Take this medicine with a full glass of water.

To be sure you get the correct dose of the oral solution (liquid), measure the liquid with a marked measuring spoon or medicine cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

Do not stop taking Tagamet without first talking to your doctor. It may take up to 8 weeks for an ulcer to heal.

Your ulcer may take longer to heal if you smoke cigarettes.

Store Tagamet at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine. Overdose symptoms may include nausea, vomiting, diarrhea, confusion, extreme weakness, or fainting.

What should I avoid while taking Tagamet?

If you also take ketoconazole (Nizoral), take it at least 2 hours before you take Tagamet.

Avoid taking antacids unless your doctor recommends them for heartburn pain. Follow your doctor's advice about the type of antacid to use and when to use it. You may not be able to take the antacid at the same time you take your dose of Tagamet.

Tagamet side effects

Stop using Tagamet and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • cough, fever, chest congestion, trouble breathing;

  • red or blistering skin rash;

  • jaundice (yellowing of the skin or eyes);

  • easy bruising or bleeding, unusual weakness;

  • feeling faint, light-headed, disoriented, or confused;

  • urinating less than usual;

  • irregular heartbeat; or

  • a rash.

Less serious side effects may include:

  • feeling dizzy, depressed, or agitated;

  • breast swelling or tenderness (in men);

  • joint or muscle pain;

  • mild skin rash;

  • headache; or

  • diarrhea, nausea, or constipation.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

What other drugs will affect Tagamet?

Before taking this medication, tell your doctor if you are using any of the following medicines:

This list is not complete and there are many other drugs that can interact with Tagamet. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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