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 Zantac®, Pepcid®, or Axid®.

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 Coumadin®), theophylline (Theo-Dur®, Slo-bid®), aminophylline, beta-blocker medicines (Tenormin®, Lopressor®, Inderal®), or phenytoin (Dilantin®).
• 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

If you notice other side effects that you think are caused by this medicine, tell your doctor.