Drugs Information Online
Drugs and diseases reference index

Drugs and diseases reference index

Drugs A-Z List

Diseases & Conditions A-Z List

Herbs & Supplements

Medical Dictionary

Full Article

Popular Drugs

Popular Diseases & Conditions

Drugs reference index «Cimetidine»



Brand names: Tagamet HB, Tagamet

Why is Cimetidine prescribed?

Tagamet is prescribed for the treatment of certain kinds of stomach and intestinal ulcers and related conditions. These include: active duodenal (upper intestinal) ulcers; active benign stomach ulcers; erosive gastroesophageal reflux disease (backflow of acid stomach contents); prevention of upper abdominal bleeding in those who are critically ill; and excess-acid conditions such as Zollinger-Ellison syndrome (a form of peptic ulcer with too much acid). It is also used for maintenance therapy of duodenal ulcer following the healing of active ulcers. Tagamet is known as a histamine blocker.

Tagamet HB 200 is an over-the-counter version of the drug used to relieve and prevent heartburn, acid indigestion, and sour stomach.

Most important fact about Cimetidine

Short-term treatment with Tagamet can result in complete healing of a duodenal ulcer. However, there can be a recurrence of the ulcer after Tagamet has been discontinued. The rate of ulcer recurrence may be slightly higher in people healed with Tagamet rather than other forms of therapy. However, Tagamet is usually prescribed for more severe cases.

How should you take Cimetidine?

You can take Tagamet with or between meals. Do not take antacids within 1 to 2 hours of a dose of Tagamet. Avoid excessive amounts of caffeine while taking Cimetidine.

It may take several days for Tagamet to begin relieving stomach pain. Be sure to continue taking the drug exactly as prescribed even if it seems to have no effect.

Do not take the maximum daily dose of Tagamet HB for more than 2 weeks continuously without consulting your doctor.

  • If you miss a dose...Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at once.
  • Storage instructions...Store at room temperature in a tightly closed container, away from light.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Tagamet.

  • Side effects may include:Breast development in men, headache

Less common side effects—agitation, anxiety, confusion, depression, disorientation, and hallucinations—may appear in severely ill individuals who have been treated for 1 month or longer. However, these reactions are not permanent and have cleared up within 3 to 4 days of discontinuation of the drug.

Why should Cimetidine not be prescribed?

If you have ever had an allergic reaction to Tagamet, do not take Cimetidine.

Special warnings about Cimetidine

Ulcers may be more difficult to heal if you smoke cigarettes.

If you are being treated for a liver or kidney disorder, make sure the doctor is aware if it.

If you are over 50 years old, have liver or kidney disease, or are severely ill, you may experience temporary mental confusion while taking Tagamet. Notify your doctor.

If you have trouble swallowing or persistent abdominal pain, do not take Tagamet HB; instead, check with your doctor. You may have a serious condition that requires different treatment.

Possible food and drug interactions when taking Cimetidine

If Tagamet is taken with certain other drugs, the effects of either can be increased, decreased, or altered. It is especially important that you check with your doctor before combining Tagamet with the following:

Antidiabetic drugsAntifungal drugs such as ketoconazoleAspirinAugmentinBenzodiazepine tranquilizersBeta-blocking blood pressure drugs such as propranololCalcium-blocking blood pressure drugs such as diltiazemChlorpromazineCisaprideCyclosporineDigoxinMedications for irregular heartbeatMetoclopramideMetronidazoleNarcotic pain relievers such as morphineNicotineParoxetinePentoxifyllinePhenytoinQuinineSucralfateTheophyllineWarfarin

Avoid alcoholic beverages while taking Tagamet. This medication increases the effects of alcohol.

Antacids can reduce the effect of Tagamet when taken at the same time. If you take an antacid to relieve the pain of an ulcer, the doses should be separated by 1 to 2 hours.

If you need to take an antifungal drug such as ketoconazole, you should take it at least 2 hours before you take Tagamet.

Special information if you are pregnant or breastfeeding

The effects of Tagamet during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, notify your doctor immediately. Tagamet appears in breast milk and could affect a nursing infant. If Cimetidine is essential to your health, your doctor may advise you to discontinue breastfeeding until treatment with Cimetidine is finished.

Recommended dosage for Cimetidine


Active Duodenal Ulcer

The usual dose is 800 milligrams once daily at bedtime. However, other doses shown to be effective are:

300 milligrams 4 times a day with meals and at bedtime

400 milligrams twice a day, in the morning and at bedtime

Most people heal in 4 weeks.

If you require maintenance therapy, the usual dose is 400 milligrams at bedtime.

Active Benign Gastric Ulcer

The usual dose is 800 milligrams once a day at bedtime or 300 milligrams taken 4 times a day with meals and at bedtime.

Erosive Gastroesophageal Reflux Disease

The usual dosage is a total of 1,600 milligrams daily divided into doses of 800 milligrams twice a day or 400 milligrams 4 times a day for 12 weeks. The beneficial use of Tagamet beyond 12 weeks has not been firmly established.

Pathological Hypersecretory Condition

The usual dosage is 300 milligrams 4 times a day with meals and at bedtime. Your doctor may adjust your dosage based on your needs, but you should take no more than 2,400 milligrams per day.


Safety and effectiveness have not been established in children under 16 years old. However, your doctor may decide that the potential benefits of Tagamet use outweigh the potential risks. Doses of 20 to 40 milligrams per 2.2 pounds of body weight have been used.


Do not give Tagamet HB 200 to children under 12 years old unless your doctor approves. Swallow tablets with a glass of water. Do not take more than 2 tablets a day or take them for longer than 2 weeks unless your doctor approves.

For Prevention of Heartburn Symptoms

Take 1 tablet with a glass of water right before or any time up to 30 minutes before eating food or drinking beverages that may cause heartburn.

For Relief of Heartburn Symptoms

Take 1 tablet with a glass of water.


Information concerning overdosage is limited. However, respiratory failure, an increased heartbeat, exaggerated side effect symptoms or reactions such as unresponsiveness may be signs of Tagamet overdose. If you experience any of these symptoms, notify your doctor immediately.

  • Cimetidine MedFacts Consumer Leaflet (Wolters Kluwer)
  • Cimetidine Prescribing Information (FDA)
  • Cimetidine Professional Patient Advice (Wolters Kluwer)
  • cimetidine Concise Consumer Information (Cerner Multum)
  • Tagamet MedFacts Consumer Leaflet (Wolters Kluwer)

See Also...

Comment «Cimetidine»