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Cimetidine (By mouth)

Cimetidine (sye-ME-ti-deen)

Treats duodenal ulcer, gastric ulcer, gastroesophageal reflux disease (GERD), and other disorders of the stomach. Also treats or prevents heartburn. This medicine is a histamine H2-blocker.

Brand Name(s):

Tagamet, Tagamet HB, TopCare Heartburn Relief

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

  • Take your medicine as directed.
  • If you are taking 1 dose daily to treat ulcers or GERD, take the medicine 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.
  • To treat heartburn, take the medicine at any time with a full glass of water. To prevent heartburn, take the medicine with water no more than 30 minutes before you eat or drink something that causes you to have heartburn. Do not take more than 2 doses each day, unless your doctor tells you otherwise. Do not use this medicine to treat heartburn for longer than 2 weeks in a row.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Do not freeze the oral liquid.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

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.
  • Make sure your doctor knows if you also use carmustine (BiCNU®), chloroquine (Aralen®), dofetilide (Tikosyn®), meperidine (Demerol®), morphine, theophylline (Theo-Dur®, Slo-Bid®), or tizanidine (Zanaflex®). Your doctor should know if you use blood thinners (such as Coumadin®), seizure medicine, or medicine to treat asthma or heart conditions.
  • Avoid large amounts of coffee or aspirin while using cimetidine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breast feeding.
  • Tell your doctor if you have a history of heart disease, kidney disease, or liver disease.
  • Make sure your doctor knows if you have painful heartburn that also causes dizziness, sweating, chest or shoulder pain, trouble breathing, or trouble swallowing. Tell your doctor if you have unexpectedly lost weight.
  • Avoid using this medicine if you are vomiting. Avoid smoking tobacco while you are using cimetidine. Smoking may cause the medicine to not work properly.
  • If you have had ongoing heartburn for 3 months or longer, you may have a serious medical problem. Stop using this medicine and call your doctor.

Possible Side Effects While Using This Medicine:

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

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Bloody or black, tarry stools.
  • Pain when you swallow.
  • Vomiting blood or material that looks like coffee grounds.
  • Yellowing of your skin or the whites of your eyes.
  • Unexplained fever, unusual bruising.

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

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

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

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088


Last Updated: 12/4/2014


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