Cimetidine (Oral)

Cimetidine (By Mouth)

Cimetidine (sye-MET-i-deen)

Treats duodenal ulcer, gastric ulcer, and other disorders of the stomach. Belongs to a class of drugs called histamine H2-blockers.

Brand Name(s):

Tagamet HB, Tagamet
There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have ever had an allergic reaction to cimetidine or other histamine H2-blockers such as Zantacreg;, Pepcidreg;, or Axidreg;.

How to Use This Medicine:

Tablet, Liquid

  • Your doctor will tell you how much medicine to take and how often.  
  • If you are taking 1 dose daily, take it at bedtime. If you are taking 2 doses daily, take one dose in the morning and one at bedtime. If you are using several doses daily, take with meals and at bedtime.  
  • Do not stop taking this medicine unless your doctor tells you to.

If a dose is missed::

  • Use your medicine as soon as you remember that you have missed your dose.  
  • If it is nearly time for your next dose, wait until then to use the medicine and skip the missed dose.  
  • You should not use two doses at one time.

How to Store and Dispose of This Medicine:

  • Keep your medicine at room temperature, away from heat and direct light. Do not freeze the oral liquid.  
  • Keep all medicine away from children.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • You should not use antacids within 1 hour before or after taking cimetidine.  
  • You should not use ketoconazole within 2 hours before or after taking cimetidine.  
  • Unless approved by your doctor, cimetidine should not be taken with antidepressant drugs, blood thinners (such as Coumadinreg;), theophylline (Theo-Durreg;, Slo-bidreg;), aminophylline, beta-blocker medicines (Tenorminreg;, Lopressorreg;, Inderalreg;), or phenytoin (Dilantinreg;).  
  • Avoid large amounts of coffee or aspirin while using cimetidine.

Warnings While Using This Medicine:

  • If you are pregnant or breastfeeding, talk to your doctor before using this medicine.  
  • Check with your doctor before using if you have a history of kidney or liver disease.  
  • Avoid smoking tobacco while you are using cimetidine. Smoking may cause the medicine to not work properly.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Yellowing of skin or eyes  
  • Unexplained fever, unusual bruising  
  • Trouble breathing  
  • Skin rash, burning, or itching

If you notice these less serious side effects, talk with your doctor:

  • Diarrhea  
  • Headache  
  • Confusion  
  • Dizziness or drowsiness  
  • Decreased sexual desire  
  • Swollen breasts

Johns Hopkins patient information

Copyright 1996-2014 Cerner Multum, Inc. Version: 16.02.
Revision date: July 9, 2011
Last revised: by Dave R. Roger, M.D.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

The drug reference included in this section is provided by Cerner Multum, Inc., of Denver, Colorado. Armenian Medical Network receives monthly updates from Multum.