Brand Names: Tagamet, Tagamet HB

Generic Name: cimetidine (Pronunciation: sye ME ti deen)

• What is cimetidine (Tagamet)?
• What are the possible side effects of cimetidine (Tagamet)?
• What is the most important information I should know about cimetidine (Tagamet)?
• What should I discuss with my healthcare provider before taking cimetidine (Tagamet)?
• How should I take cimetidine (Tagamet)?
• What happens if I miss a dose (Tagamet)?
• What happens if I overdose (Tagamet)?
• What should I avoid while taking cimetidine (Tagamet)?
• What other drugs will affect cimetidine (Tagamet)?
• Where can I get more information?

What is cimetidine (Tagamet)?

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 other purposes not listed in this medication guide.

Cimetidine 200 mg-APO

round, green, imprinted with APO 018

Cimetidine 200 mg-MYL

pentagonal, green, imprinted with 53, M

Cimetidine 200 mg-TEV

round, white, imprinted with 93, 111

Cimetidine 300 mg-APO

round, green, imprinted with APO 019

Cimetidine 300 mg-GG

round, green, imprinted with GG 428

Cimetidine 300 mg-IVA

round, white, imprinted with Z 300, 7117

Cimetidine 300 mg-MYL

pentagonal, green, imprinted with 317, M

Cimetidine 300 mg-TEV

round, white, imprinted with 93, 112

Cimetidine 300 mg-TEV8192

oval, green, imprinted with 300, N192

Cimetidine 400 mg-APO

oblong, green, imprinted with APO020

Cimetidine 400 mg-GG

oblong, green, imprinted with GG 429

Cimetidine 400 mg-IVA

oblong, white, imprinted with Z 400, 71 71

Cimetidine 400 mg-MYL

pentagonal, green, imprinted with 372, M

Cimetidine 400 mg-SAN

oblong, white, imprinted with LEK CT4

Cimetidine 400 mg-TEV

oblong, white, imprinted with 93 113

Cimetidine 800 mg-APO

oval, green, imprinted with APO021

Cimetidine 800 mg-GG

oblong, green, imprinted with GG 430

Cimetidine 800 mg-IVA

oval, white, imprinted with Z 800, 77 11

Cimetidine 800 mg-MYL

oval, green, imprinted with M 541

Cimetidine 800 mg-SAN

oval, white, imprinted with LEK CT8

What are the possible side effects of cimetidine (Tagamet)?

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.

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.

Read the Tagamet (cimetidine) Side Effects Center for a complete guide to possible side effects »

What is the most important information I should know about cimetidine (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.

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 are many other drugs that can interact with 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.

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.