Cimetidine: MedlinePlus Drug Information

T Why is this medication prescribed?
P Cimetidine is used to treat ulcers; gastroesophageal reflux disease (GERD), a condition in which backward flow of acid from the stomach causes heartburn and injury of the food pipe (esophagus); and conditions where the stomach produces too much acid, such as Zollinger-Ellison syndrome. Over-the-counter cimetidine is used to prevent and treat symptoms of heartburn associated with acid indigestion and sour stomach. Cimetidine is in a class of medications called H2 blockers. It decreases the amount of acid made in the stomach.

T How should this medicine be used?
P Cimetidine comes as a tablet and a liquid to take by mouth. It is usually taken once a day at bedtime or two to four times a day with meals and at bedtime. Over-the-counter cimetidine is usually taken once or twice a day with a glass of water. To prevent symptoms, it is taken within 30 minutes before eating or drinking foods that cause heartburn. Follow the directions on your prescription or the package label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take cimetidine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
P Do not take over-the-counter cimetidine for longer than 2 weeks unless your doctor tells you to. If symptoms of heartburn, acid indigestion, or sour stomach last longer than 2 weeks, stop taking cimetidine and call your doctor.

T Other uses for this medicine
P Cimetidine is also used sometimes to treat stress ulcers, hives and itching, and viral warts, and to prevent aspiration pneumonia during anesthesia. Talk to your doctor about the possible risks of using this medication for your condition.
P This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

T What special precautions should I follow?
t Before taking cimetidine,
- tell your doctor and pharmacist if you are allergic to cimetidine or any other medications.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the following: anticoagulants ('blood thinners') such as warfarin (Coumadin); antidepressants (mood elevators) such as amitriptyline (Elavil), amoxapine (Asendin), clomipramine (Anafranil), desipramine (Norpramin), doxepin (Adapin, Sinequan), imipramine (Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil); chlordiazepoxide (Librium); clopidogrel (Plavix), diazepam (Valium); lidocaine (Xylocaine); metronidazole (Flagyl); nifedipine (Adalat, Procardia); phenytoin (Dilantin); propranolol (Inderal); and theophylline (Theobid, Theo-Dur). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- if you are taking antacids (Maalox, Mylanta, Tums), digoxin (Lanoxin), ketoconazole (Nizoral), or iron salts, take them 2 hours before cimetidine.
- tell your doctor if you have or have ever had human immunodeficiency virus (HIV), acquired immunodeficiency syndrome (AIDS), or kidney or liver disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking cimetidine, call your doctor.
- talk to your doctor about the risks and benefits of taking cimetidine if you are 65 years of age or older. Older adults should not usually take cimetidine because it is not as safe as other medication(s) that can be used to treat the same condition.

T What special dietary instructions should I follow?
P Unless your doctor tells you otherwise, continue your normal diet.

T What should I do if I forget a dose?
P Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

T What side effects can this medication cause?
t Cimetidine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- headache
- diarrhea
- dizziness
- drowsiness
- breast enlargement
t Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, call your doctor immediately:
- confusion
- excitement
- depression
- nervousness
- seeing things or hearing voices that do not exist (hallucinating)
P Cimetidine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
P If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

T What should I know about storage and disposal of this medication?
P Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).
P Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.
P It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

T In case of emergency/overdose
P In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

T What other information should I know?
P Keep all appointments with your doctor.
P Do not let anyone else take your medicine. Ask your pharmacist any questions you have about refilling your prescription.
P It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

T Brand names
- Tagamet®
- Tagamet® HB

