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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.

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What is the price of this medication and similar alternatives?

Pricing information provided by drugstore.com.

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What are the possible side effects of cimetidine?

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:

• 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.

Other less serious side effects are more likely to occur. Talk with your doctor if you have any of these side effects:

• feeling dizzy, depressed, or agitated;

• breast swelling or tenderness (in men);

• joint or muscle pain;

• mild skin rash;

• headache; or

• 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.

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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.

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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.

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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.

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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: a blood thinner (warfarin or Coumadin); phenytoin (Dilantin); nifedipine (Adalat); metronidazole (Flagyl); propranolol (Inderal); chlordiazepoxide (Librium); lidocaine (Xylocaine); diazepam (Valium); theophylline (Theo-Dur, Slo-Bid, Bronkodyl); or depression or anxiety medication such as amitriptyline (Elavil), imipramine (Tofranil), clomipramine (Anafranil), desipramine (Norpramin), nortripytyline (Aventyl).

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Cimetidine has been assigned to pregnancy category B by the FDA. Animal studies have failed to reveal evidence of fetal harm. There are no controlled data in human pregnancy. Cimetidine crosses the placenta, bidirectionally, by slow, passive diffusion. However, cimetidine has been used safely during pregnancy to treat severe peptic ulcer disease as well as near term for the prevention of Mendelson's syndrome. Cimetidine is only recommended for use during pregnancy when benefit outweighs risk.

Placental transfer of cimetidine is slow. In one study, the fetal/maternal ratio averaged 0.46 two hours after intravenous administration of cimetidine to the maternal placental circuit. Administration to both the fetal and maternal circuits resulted in equilibrium, with the fetal/maternal ratio averaging 1.01, for the duration of the two hour experiment. These data suggest that chronic dosing would result in increased exposure to the fetus compared to exposure following a single dose during labor. There are no adequate data on the safety of cimetidine during the first trimester. Cimetidine has been used safely and successfully during labor to prevent Mendelson's syndrome. The use of cimetidine in this setting does not affect the duration of labor or the pattern or intensity of contractions. Adverse fetal and neonatal effects have not been found in several studies documenting the use of cimetidine during labor and delivery.

Cimetidine is excreted into human milk. While the manufacturer recommends avoiding use during lactation, cimetidine is considered compatible with breast-feeding by the American Academy of Pediatrics.

Following oral administration of cimetidine 400 mg in one patient, the peak milk concentration was 5 mcg/mL. The milk to plasma ratio ranged from 3.04 to 3.57. Following a chronic dosing regimen in the same patient, cimetidine milk concentrations remained relatively constant, with milk to plasma ratios greater, although variable, than those noted in the single dose study. The authors suggest an active transport mechanism is involved.

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Who should NOT use this medication?

• Known hypersensitivity to cimetidine or any ingredient in the formulation.

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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. Tagamet 200 mg--round, light-green, film-coated tablets Tagamet 300 mg--round, light-green, film-coated tablets Tagamet 400 mg--oval, light-green, film-coated tablets Tagamet 800 mg--oval, light-green, film-coated tablets

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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.

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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: diabetes; asthma or a chronic lung disorder; a weak immune system; bone marrow suppression; kidney disease; or 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.

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Can I stop taking the medication if I feel better?
As a general rule, you should always take your medications exactly as prescribed and do not change the dosage or stop taking the medication without first discussing it with your healthcare provider.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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Where can I get more information?
More Information

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