Generic Name: Cimetidine (sye-MET-i-deen)Brand Name: Tagamet

Cimetidine is used for:

Treating and preventing ulcers of the stomach and small intestine, and treating gastroesophageal reflux disease (GERD). It may be used for treating esophagitis (inflammation of the esophagus) caused by acid reflux and certain conditions that cause increased acid secretion (eg, Zollinger-Ellison syndrome). It may also be used to treat other conditions as determined by your doctor.

Cimetidine is an H2(histamine) blocker. It works by blocking one of the chemicals, histamine, that stimulates the release of acid into the stomach. This reduces acidity in the stomach.

Do NOT use Cimetidine if:

  • you are allergic to any ingredient in Cimetidine
  • you are taking medicine for cancer (nitrosoureas)
  • you are taking cisapride, dofetilide, or a nitrosoureas (eg, carmustine)

Contact your doctor or health care provider right away if any of these apply to you.

Before using Cimetidine :

Some medical conditions may interact with Cimetidine . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have liver or kidney problems

Some MEDICINES MAY INTERACT with Cimetidine . Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Many prescription medicines (eg, those used for angina, asthma, arrhythmias, blood thinning, cancer, erectile dysfunction, high blood pressure, infections, pain, psychiatric disorders, seizures, other conditions) may interact with Cimetidine , increasing the risk of side effects, some potentially life-threatening.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Cimetidine may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Cimetidine :

Use Cimetidine as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take Cimetidine by mouth with or without food.
  • Do not take an antacid within 1 hour before or after you take Cimetidine .
  • If you also take cephalosporin (eg, cephalexin), itraconazole, or ketoconazole, take it at least 2 hours before taking Cimetidine . Check with your doctor if you have questions.
  • If you miss a dose of Cimetidine and you are taking it regularly, use it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not use 2 doses at once.

Ask your health care provider any questions you may have about how to use Cimetidine .

Important safety information:

  • Cimetidine may cause dizziness or drowsiness. These effects may be worse if you take it with alcohol or certain medicines. Use Cimetidine with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • It may be necessary to make significant lifestyle changes to assist in the treatment and prevention of ulcers and other digestive problems that include stress-reduction programs, exercise, and dietary changes.
  • If your symptoms do not get better within a few days, or if they get worse, check with your doctor.
  • Never self-diagnose or self-treat ulcers with this or any other medicine.
  • Notify your doctor if you experience black, tarry stools or vomit that looks like coffee grounds.
  • Do not drink alcohol while you are using Cimetidine .
  • Do not smoke or use other tobacco products while using Cimetidine .
  • Additional monitoring of your dose or condition may be necessary if you are also taking zaleplon.
  • Use Cimetidine with caution in the ELDERLY; they may be more sensitive to its effects.
  • Cimetidine should be used with extreme caution in CHILDREN younger than 16 years old; safety and effectiveness have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Cimetidine while you are pregnant. Cimetidine is found in breast milk. Do not breast-feed while taking Cimetidine .

Possible side effects of Cimetidine :

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Diarrhea; dizziness; drowsiness; headache.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); agitation; anxiety; breast enlargement; breast lumps; confusion; depression; disorientation; fatigue; hallucinations; hair loss; joint or muscle pain; pain, redness or swelling at injections site; skin flushing or redness; sexual difficulties; slow or fast heartbeat.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects at

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center (, or emergency room immediately. Symptoms may include difficulty breathing; fast heartbeat; restlessness; tremors; vomiting.

Proper storage of Cimetidine :

Store Cimetidine at room temperature between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Cimetidine out of the reach of children and away from pets.

General information:

  • If you have any questions about Cimetidine , please talk with your doctor, pharmacist, or other health care provider.
  • Cimetidine is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.

This information is a summary only. It does not contain all information about Cimetidine . If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.

  • Cimetidine Prescribing Information (FDA)
  • Cimetidine Professional Patient Advice (Wolters Kluwer)
  • Cimetidine Detailed Consumer Information (PDR)
  • cimetidine Concise Consumer Information (Cerner Multum)