The following information is a summary about Tagamet. It is not intended to replace a doctor's instructions.
What is cimetidine?
Cimetidine is in a group of drugs called histamine receptor antagonists. Cimetidine works
by decreasing the amount of acid your stomach produces.
Cimetidine is used to treat and prevent certain types of ulcer, and to treat conditions that
cause the stomach to produce too much acid. Cimetidine is also used to treat gastroesophageal
reflux disease (GERD), when stomach acid backs up into the esophagus and causes heartburn.
Cimetidine may also be used for conditions other than those listed in this medication
guide.
What is the most important information I should know about cimetidine?
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 cimetidine.
Taking cimetidine 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 cimetidine, tell your doctor if you have any of
these conditions.
There may be other drugs that can affect cimetidine. 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.
What should I discuss with my healthcare provider before taking cimetidine?
Taking cimetidine may make you more susceptible to virus that causes pneumonia. You
may be more likely to develop pneumonia if you have certain health problems.
Before using this medication, tell your doctor if you have:
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diabetes;
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asthma or a chronic lung disorder;
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a weak immune system;
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bone marrow suppression;
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kidney disease; or
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liver disease.
If you have any of the conditions listed above, you may not be able to
use cimetidine or you may need a dosage adjustment or special tests during treatment.
Cimetidine 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.
Cimetidine passes into breast milk, and may be harmful to a nursing baby. Do not
take cimetidine 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 cimetidine?
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.
Cimetidine is usually taken with meals or at bedtime.
Take each dose 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 cimetidine 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 cimetidine 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. Symptoms of a cimetidine overdose may include nausea, vomiting, diarrhea,
confusion, extreme weakness, or fainting.
What should I avoid while taking cimetidine?
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 cimetidine.
Cimetidine side effects
Stop using cimetidine 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:
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cough, fever, chest congestion, trouble breathing;
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red or blistering skin rash;
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jaundice (yellowing of the skin or eyes);
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easy bruising or bleeding, unusual weakness;
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feeling faint, light-headed, disoriented, or confused;
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urinating less than usual;
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irregular heartbeat; or
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a rash.
Other less serious side effects are more likely to occur. Talk with your
doctor if you have any of these side effects:
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feeling dizzy, depressed, or agitated;
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breast swelling or tenderness (in men);
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joint or muscle pain;
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mild skin rash;
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headache; or
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diarrhea, nausea, or constipation.
Side effects other than those listed here may also occur. Talk to your
doctor about any side effect that seems unusual or that is especially bothersome.
What other drugs will affect cimetidine?
If you also take ketoconazole (Nizoral), take it at least 2 hours before you take cimetidine.
Before taking this medication, tell your doctor if you are using any of the following
medicines:
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a blood thinner (warfarin or Coumadin);
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phenytoin (Dilantin);
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nifedipine (Adalat);
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metronidazole (Flagyl);
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propranolol (Inderal);
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chlordiazepoxide (Librium);
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lidocaine (Xylocaine);
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diazepam (Valium);
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theophylline (Theo-Dur, Slo-Bid, Bronkodyl); or
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depression or anxiety medication such as amitriptyline
(Elavil), imipramine (Tofranil), clomipramine (Anafranil), desipramine (Norpramin),
nortripytyline (Aventyl).
You may not be able to take cimetidine, or you may require a dosage
adjustment or special monitoring during treatment if you are taking any of the medicines listed
above.
There may be other drugs not listed that can affect cimetidine. 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.
Where can I get more information?
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Your pharmacist has additional information about cimetidine written for health
professionals that you may read.
What does my medication look like?
Cimetidine is available with a prescription under the brand name Tagamet. It is also
available over the counter under the brand name Tagamet HB. Other brand or generic
formulations may also be available. Ask your pharmacist any questions you have about this
medication, especially if it is new to you.
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Tagamet 200 mg--round, light-green, film-coated tablets
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Tagamet 300 mg--round, light-green, film-coated tablets
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Tagamet 400 mg--oval, light-green, film-coated tablets
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Tagamet 800 mg--oval, light-green, film-coated tablets
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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.
