(cimetidine hydrochloride)
Brands
Tagamet, Cimetidine
Availability
- Tablets: 100 mg, 200 mg (avail. in higher mg tablets as well).
- Syrup: 40 mg/mL
- Cimetidine HCL liquid: 300 mg/5mL
Pharmacology
Cimetidine is an H2 receptor antagonist, which competitively blocks histamine to decrease daytime and nocturnal gastric acid secretion.
It inhibits gastric secretions stimulated by the following: food, insulin, pentagastrin, and histamine; however, gastric emptying and lower esophageal pressure are not altered by this drug.
It has a demonstrated effect on reversal of suppressor T cell-mediated immunity.
Cimetidine is well absorbed by way of the GI tract and distributed in tissues. It is able to cross placental barrier.
It is metabolized in the liver, excreted in the kidneys, and through breast milk.
Indications
Used to treat gastric and duodenal ulceration, esophagitis and gastroesophageal reflux. Also used to treat in mega-esophagus by reducing gastric secretions.
Drug Interactions or Contraindications
- Use cautiously in impaired hepatic and renal functions.
- May increase serum levels of beta blocking agents, lidocaine, calcium channel blockers, benzodiazepines, metronidazole, phenytoin, quinidine, and theophylline.
- Decreases renal clearance of procainamide.
- May be incompatible with amphotericin B, ampicillin sodium, cefazolin sodium, pentobarbital sodium.
Adverse Reactions
CNS: disorientation
CV: cardiac arrhythmias
GI: diarrhea
Skin: pruritus (itching), pain
Blood: agranulocytosis
Dosage Recommendations
5 mg/kg to 10 mg/kg, PO, SQ, IM, q6hr to q12hr 1, 2, 27, 41, 42, 44
Considerations
- In the event of respiratory failure beta-adrenergic blockers may be given.
- Store tablets in a tightly closed container, away from light, at room temperature.
- Do not refrigerate injectables since they may precipitate.
