cimetidine, Tagamet

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GENERIC NAME: cimetidine

BRAND NAME: Tagamet, Tagamet HB

DRUG CLASS AND MECHANISM: Cimetidine is an drug that blocks the production of acid by acid-producing cells in the stomach and can be administered orally, IM or IV. It belongs to a class of drugs called H2 (histamine-2) blockers that also includes ranitidine (Zantac), nizatidine (Axid), and famotidine (Pepcid). Histamine is a naturally-occurring chemical that stimulates cells in the stomach (parietal cells) to produce acid. H2-blockers inhibit the action of histamine on the cells, thus reducing the production of acid by the stomach. Since excessive stomach acid can damage the esophagus, stomach, and duodenum by reflux and lead to inflammation and ulceration, reducing stomach acid prevents and allows acid-induced inflammation and ulcers to heal. Cimetidine was approved by the FDA in 1977.

PRESCRIPTION: Yes and OTC (Heart Burn)

GENERIC AVAILABLE: Yes

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

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

PRESCRIBED FOR: Cimetidine is used for the treatment of duodenal ulcers, active gastric ulcers, gastroesophageal reflux disease (GERD), pathological hypersecretory conditions (for example, Zollinger Ellison syndrome), heartburn and the prevention of gastrointestinal bleeding.

DOSING:

Duodenal ulcers are treated with 800 to 1600 mg at bedtime or 300 mg 4 times a day at meal times and bedtime, or 400 mg twice a day for 4-6 weeks. Maintenance therapy is 400 mg at bedtime.

Active gastric ulcers are treated with 800 mg at bedtime or 300 mg 4 times a day at meal times and bedtime for up to 8 weeks.

The regimen for GERD is 800 mg twice a day or 400 mg 4 times a day for 12 weeks.

Pathological hypersecretory conditions are treated with 300 mg 4 times daily up to 2400 mg daily.

Heartburn, indigestion and/or sour stomach may be treated with 200 mg once or twice daily and may be administered up to 30 minutes before ingestion of food or beverages that may cause heartburn.

For hospitalized patients who cannot take oral medications, 300 mg of cimetidine may be administered by intravenous or intramuscular injection every 6-8 hours. A continuous intravenous infusion of 37.5 to 50 mg/hour also may be used.

Other dosages of IV or IM cimetidine may be used for erosive esophagitis, upper GI bleeding or other conditions; use in these situations may be best determined by a GI specialist.

DRUG INTERACTIONS: 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).

Medically Reviewed by a Doctor on 6/13/2014



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