Cimetidine

Cimetidine may increase the blood levels of several drugs by reducing their elimination by the liver. This interaction may occur between cimetidine and warfarin (Coumadin), a commonly used blood thinning agent. Patients taking both medications should have frequent blood monitoring to avoid accumulation of high levels of warfarin leading to excessive blood thinning and bleeding.

Cimetidine also may increase the blood levels phenytoin (Dilantin, Dilantin-125), theophylline (Respbid, Slo-Bid, Theo-24, Theolair), lidocaine, amiodarone (Cordarone), metronidazole (Flagyl), loratadine, calcium channel blockers (for example, diltiazem (Cardizem, Dilacor, Tiazac), felodipine (Plendil), nifedipine (Adalat, Procardia, Afeditab, Nifediac), bupropion (Wellbutrin, Wellbutrin SR, Wellbutrin XL, Zyban, Aplenzin, Forfivo XL), carbamazepine (Tegretol Tegretol XR, Equetro, Carbatrol), and fluvastatin (Lescol, Lescol XL).

Because cimetidine reduces stomach acid, it may reduce the absorption of drugs (for example, ketoconazole [Nizoral, Extina, Xolegel, Kuric]) that are best absorbed in acidic conditions. Such drugs should be administered at least 2 hours before the administration of cimetidine.

Tablets: 200, 300, 400, and 800 mg. Liquid: 300 mg/5 ml. Injection: 150 mg/ml.

Store at room temperature 15 C to 30 C (59 F to 86 F).

Purpose

Acid reducer

Uses

• relieves heartburn associated with acid indigestion and sour stomach
• prevents heartburn associated with acid indigestion and sour stomach brought on by eating ordrinking certain foods and beverages

Active Ingredient

(in each tablet) Cimetidine 200mg

Inactive Ingredients

cellulose, corn starch, hypromellose, magnesium stearate, polyethylene glycol, polysorbate 80, povidone, sodium lauryl sulfate, sodium starch glycolate, titanium dioxide

Keep out of reach of children.

Questions or comments?

call toll-free 1-800-482-4394 (English/Spanish) weekdays

Medtech Products Inc. Revised: 2014

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• Oral cancer medications like bosutinib (Bosulif), dasatinib (Sprycel), ibrutinib (Imbruvica), olaparib (Lynparza), and pazopanib (Votrient)
• Dofetilide (Tikosyn)
• Certain anti-viral medications like delavirdine (Rescriptor) and Simeprevir (Olysio)
• Risedronate (Actonel)
• Clopidogrel (Plavix)
• Warfarin (Coumadin)
• Medications that block the p-glycoprotein transporter such as amiodarone (Cordarone, Pacerone), azithromycin (Zithromax, Zmax), captopril (Capoten), carvedilol (Coreg), clarithromycin (Biaxin), conivaptan (Vaprisol), cyclosporine (Neoral, Sandimmune, Gengraf), diltiazem (Cardizem), dronedarone (Multaq), erythromycin (EES, Ery-Tab), felodipine (Plendil),  itraconazole (Sporanox, Onmel), ketoconazole (Nizoral), lopinavir and ritonavir (Kaletra), quinidine (Cardioquine, Quinact, Duraquin), ranolazine (Ranexa), and verapamil (Calan, Isoptin, Covera, Verelan)
• Medications that use the enzyme CYP3A4 such as budesonide (Entocort), astemizole (Hismanal), cisapride (Propulsid), cyclosporine (Neoral, Gengraf, Sandimmune), darifenacin (Enablex), dihydroergotamine (Migranal), fentanyl (Abstral, Fentora, Onsolis, Actiq), pimozide (Orap), quinidine (Cardioquin, Duraquin, Quinact), sirolimus (Rapamune), tacrolimus (Prograf), terfenadine (Seldane), fluticasone (Flovent HFA, Flonase), eletriptan (Relpax), lovastatin (Mevacor), quetiapine (Seroquel), sildenafil (Viagra, Revatio), and simvastatin (Zocor)
• Medications that use the enzyme CYP1A2 such as alosetron (Lotronex), caffeine, clozapine (Clozaril), flutamide (Eulexin), frovatriptan (Frova), melatonin, mexiletine (Mexitil),  mirtazapine (Remeron), olanzapine (Zyprexa), ramelteon (Rozerem), rasagiline (Azilect), ropinirole (Requip), tacrine (Cognex), theophylline, tizanidine (Zanaflex), triamterene (Dyrenium), zolmitriptan (Zomig)
• Medications that use the enzyme CYP2D6 such as desipramine, dextromethorphan, atomoxetine, and metoprolol

This is not a complete list of drug interactions. Ask your doctor or pharmacist for more information.

• Store cimetidine at room temperature.
• Keep this and all medicines out of the reach of children.
• Keep away from light.

Cimetidine is in a group of drugs called histamine receptor antagonists. Cimetidine works by decreasing the amount of acid your stomach produces.

Cimetidine is used to treat and prevent certain types of ulcer, and to treat conditions that cause the stomach to produce too much acid. Cimetidine is also used to treat gastroesophageal reflux disease (GERD), when stomach acid backs up into the esophagus and causes heartburn.

Cimetidine may also be used for other purposes not listed in this medication guide.

Use this medication exactly as directed on the label, or as your doctor has prescribed it for you. Do not use more of the medication than recommended. Do not use the medication for longer than recommended.

Avoid taking antacids unless your doctor recommends them for heartburn pain. Follow your doctor's advice about the type of antacid to use and when to use it. You may not be able to take the antacid at the same time you take your dose of cimetidine.

Taking cimetidine may make you more susceptible to virus that can cause pneumonia. This has occurred most often in elderly people and in those with diabetes, a weak immune system, or chronic lung disease. Before using cimetidine, tell your doctor if you have any of these conditions.

There are many other drugs that can interact with cimetidine. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Heartburn can be confused with early symptoms of heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, dizziness, pain spreading to the arm or shoulder, sweating, nausea or vomiting, and a general ill feeling.

Heartburn can be confused with early symptoms of heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, dizziness, pain spreading to the arm or shoulder, sweating, nausea or vomiting, and a general ill feeling.

Taking cimetidine may make you more susceptible to virus that causes pneumonia. You may be more likely to develop pneumonia if you have certain health problems.

Ask a doctor or pharmacist if it is safe for you to take cimetidine if you have:

• diabetes;

• asthma or a chronic lung disorder;

• a weak immune system;

• bone marrow suppression;

• kidney disease; or

• liver disease.

Cimetidine is in the FDA pregnancy category B. This means that it is not expected to be harmful to an unborn baby. Do not use this medication without telling your doctor if you are pregnant or plan to become pregnant during treatment.

Cimetidine passes into breast milk, and may be harmful to a nursing baby. Do not take cimetidine without telling your doctor if you are breast-feeding a baby.

Do not give this medicine to a child younger than 16 years old unless your doctor has told you to.

Seek emergency medical attention if you think you have used too much of this medicine. Overdose symptoms may include nausea, vomiting, diarrhea, confusion, extreme weakness, or fainting.

Before taking this medication, tell your doctor if you are using any of the following medicines:

• a blood thinner (warfarin or Coumadin);

• clopidogrel (Plavix);

• phenytoin (Dilantin);

• nifedipine (Adalat);

• metronidazole (Flagyl);

• propranolol (Inderal);

• chlordiazepoxide (Librium);

• lidocaine (Xylocaine);

• diazepam (Valium);

• theophylline (Elixophyllin, Theo-24, Uniphyl); or

• depression or anxiety medication such as amitriptyline (Elavil), imipramine (Tofranil), clomipramine (Anafranil), desipramine (Norpramin), nortripytyline (Aventyl).

This list is not complete and there are many other drugs that can interact with cimetidine. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

300 mg/5 mL

Cimetidine is contraindicated for patients known to have hypersensitivity to the product.

Refer to adult dosing.

There are no dosage adjustments provided in the manufacturer’s labeling; use with caution. Dosage adjustments may be needed in patients with both renal and hepatic impairment.

CBC, gastric pH; monitor renal function to correct dose; occult blood with GI bleeding; signs of confusion.

Applies to cimetidine: oral liquid and tablets, parenteral injection, parenteral injection for iv infusion only

Side effects include:

Headache, dizziness, somnolence, diarrhea.

With ≥1 month of therapy: gynecomastia.

With IM therapy: transient pain at injection site.

200 mg orally right before (or up to 30 minutes) eating. Maximum per 24 hours: 2 doses.

Neonatal: 5 to 10 mg/kg/day administered IV or IM in divided doses every 8 to 12 hours.

Infants: 10 to 20 mg/kg/day administered IV, IM, or oral in divided doses every 6 to 12 hours.

Children: 20 to 40 mg/kg/day administered IV, IM, or oral in divided doses every 6 hours.

Summary of Use during Lactation

Limited information indicates that maternal cimetidine results in infant dosages much less than those given directly to neonates. Cimetidine would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. However, because of its potential for causing hepatic enzyme inhibition, other drugs might be preferred.

Drug Levels

Maternal Levels. After a single oral dose of 400 mg of cimetidine, the peak milk level of 5 mg/L occurred about 3 hours after the dose and was about equal to the peak serum level in a woman who had been breastfeeding for 6 months. Milk levels remained higher than serum levels for the duration of the dosing interval. With a multiple-dose regimen of 200 mg 3 times daily and 400 mg at bedtime, milk levels just prior to the doses were relatively constant between 4.9 and 6 mg/L.[1] These levels indicate that a fully breastfed infant would receive between 0.74 and 0.9 mg/kg daily which is much less than reported neonatal dosages of 5 to 10 mg/kg daily.

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Histamine H2-receptor blockade is known to stimulate prolactin secretion. Cimetidine may also have additional, nonspecific actions that stimulate prolactin secretion.[2] Oral cimetidine doses of 400 mg 4 times daily increased serum prolactin by 50 to 112% in 6 patients and caused gynecomastia and galactorrhea in nonnursing individuals.[3][4] The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider

Famotidine, Nizatidine, Omeprazole, Pantoprazole, Ranitidine, Sucralfate

References

1. Somogyi A, Gugler R. Cimetidine excretion into breast milk. Br J Clin Pharmacol. 1979;7:627-9. Letter. PMID: 465286

2. Knigge UP. Histaminergic regulation of prolactin secretion. Dan Med Bull. 1990;37:109-24. PMID: 2188799

3. Delle Fave FG, Tamburrano G, De Magistris L et al. Gynaecomastia with cimetidine. Lancet. 1977;309:1319. PMID: 68422

4. Bateson MC, Browning MCK, Maconnachie A. Galactorrhoea with cimetidine. Lancet. 1977;310:247-8. Letter. PMID: 69853