Ranitidin - General Information
A non-imidazole blocker of those histamine receptors that mediate gastric secretion (H2 receptors). It is used to treat gastrointestinal ulcers. [PubChem]
Pharmacology of Ranitidin
Ranitidin is a histamine H2-receptor antagonist similar to cimetidine and famotidine. An H2-receptor antagonist, often shortened to H2 antagonist, is a drug used to block the action of histamine on parietal cells in the stomach, decreasing acid production by these cells. These drugs are used in the treatment of dyspepsia, however their use has waned since the advent of the more effective proton pump inhibitors. Like the H1-antihistamines, the H2 antagonists are inverse agonists rather than true receptor antagonists.
Ranitidin for patients
Phenylketonurics: ZANTAC 25 EFFERdose Tablets contain phenylalanine 2.81 mg per 25 mg of ranitidine. ZANTAC 150 EFFERdose Tablets contain phenylalanine 16.84 mg per 150 mg of ranitidine. ZANTAC EFFERdose Tablets should not be chewed, swallowed whole, or dissolved on the tongue.
Coadministration of TRITEC with clarithromycin resulted in increased plasma ranitidine concentrations (57%), increased plasma bismuth trough concentrations (48%), and increased 14- hydroxy- clarithromycin plasma concentrations (31%). Coadministration with aspirin results in a slight decrease in the rate of salicylate absorption that is clinically unimportant. Coadministration with a high dose of antacid (170 mEq) results in a 28% decrease in plasma concentrations of ranitidine and may decrease plasma concentrations of bismuth from TRITEC. These effects are clinically insignificant.
For information on drug interactions associated with ranitidine, refer to the ZANTAC ® package insert.
TRITEC is contraindicated in patients known to have hypersensitivity to ranitidine bismuth citrate or any of its ingredients.
For information on clarithromycin contraindications, see clarithromycin package insert.
Additional information about Ranitidin
Ranitidin Indication: Used in the treatment of peptic ulcer disease (PUD), dyspepsia, stress ulcer prophylaxis, and gastroesophageal reflux disease (GERD).
Mechanism Of Action: The H2 antagonists are competitive inhibitors of histamine at the parietal cell H2 receptor. They suppress the normal secretion of acid by parietal cells and the meal-stimulated secretion of acid. They accomplish this by two mechanisms: histamine released by ECL cells in the stomach is blocked from binding on parietal cell H2 receptors which stimulate acid secretion, and other substances that promote acid secretion (such as gastrin and acetylcholine) have a reduced effect on parietal cells when the H2 receptors are blocked.
Drug Interactions: Anisindione The anti-H2 increases the anticoagulant effect
Dicumarol The anti-H2 increases the anticoagulant effect
Acenocoumarol The anti-H2 increases the anticoagulant effect
Warfarin The anti-H2 increases the anticoagulant effect
Itraconazole The anti-H2 decreases the absorption of the imidazole
Ketoconazole The anti-H2 decreases the absorption of the imidazole
Procainamide The histamine H2-receptor antagonist increases the effect of procainamide
Dasatinib Possible decreased levels of dasatinib
Atazanavir This gastric pH modifier decreases the levels/effects of atazanaivr
Tolazoline Anticipated loss of efficacy of tolazoline
Food Interactions: Avoid alcohol.
Avoid milk, calcium containing dairy products, iron, antacids, or aluminum salts 2 hours before or 6 hours after using antacids while on this medication.
Avoid excessive quantities of coffee or tea (Caffeine).
Generic Name: Ranitidine
Synonyms: Ranitidine hydrochloride; Ranitidine HCL; Ranitidine Base; Rantidine HCL
Drug Category: Anti-Ulcer Agents; Histamine H2 Antagonists
Drug Type: Small Molecule; Approved
Absorption: Approximately 50% bioavailability orally.
Toxicity (Overdose): LD50=77mg/kg (orally in mice). Symptoms of overdose include muscular tremors, vomiting, and rapid respiration.
Protein Binding: 15%
Biotransformation: Hepatic. Ranitidine is metabolized to the N-oxide, S-oxide, and N-desmethyl metabolites, accounting for approximately 4%, 1%, and 1% of the dose, respectively.
Half Life: 2.8-3.1 hours
Dosage Forms of Ranitidin: Solution Intravenous
Chemical IUPAC Name: (E)-N-[2-[[5-(dimethylaminomethyl)furan-2-yl]methylsulfanyl]ethyl]-N'-methyl-2-nitroethene-1,1-diamine
Chemical Formula: C13H22N4O3S
Ranitidine on Wikipedia: https://en.wikipedia.org/wiki/Ranitidine
Organisms Affected: Humans and other mammals