Cimetidine
Generic Name: cimetidine
Brand Names:
Cimetidine
DESCRIPTION Cimetidine is a histamine H 2 -receptor antagonist. Chemically it is N" -cyano- N -methyl- N' -[2-[[(5-methyl-1 H -imidazol-4-yl)methyl]thio]-ethyl]guanidine. Its structural formula is: Cimetidine contains an imidazole ring, and is chemically related to histamine. Cimetidine has a bitter taste and characteristic odor. Structural Formula Solubility Characteristics Cimetidine is soluble in alcohol, slightly soluble in water, very slightly soluble in chloroform and insoluble in ether.
Overview
DESCRIPTION Cimetidine is a histamine H 2 -receptor antagonist. Chemically it is N" -cyano- N -methyl- N' -[2-[[(5-methyl-1 H -imidazol-4-yl)methyl]thio]-ethyl]guanidine. Its structural formula is: Cimetidine contains an imidazole ring, and is chemically related to histamine. Cimetidine has a bitter taste and characteristic odor. Structural Formula Solubility Characteristics Cimetidine is soluble in alcohol, slightly soluble in water, very slightly soluble in chloroform and insoluble in ether.
Uses
INDICATIONS AND USAGE Cimetidine tablets are indicated in: 1. Short-term treatment of active duodenal ulcer. Most patients heal within 4 weeks and there is rarely reason to use cimetidine tablets at full dosage for longer than 6 to 8 weeks (see DOSAGE AND ADMINISTRATION: Duodenal Ulcer ). Concomitant antacids should be given as needed for relief of pain. However, simultaneous administration of cimetidine tablets and antacids is not recommended, since antacids have been reported to interfere with the absorption of cimetidine. 2. Maintenance therapy for duodenal ulcer patients at reduced dosage after healing of active ulcer. Patients have been maintained on continued treatment with cimetidine tablets 400 mg at bedtime for periods of up to 5 years. 3.
Dosage
DOSAGE AND ADMINISTRATION Duodenal Ulcer Active Duodenal Ulcer Clinical studies have indicated that suppression of nocturnal acid is the most important factor in duodenal ulcer healing (see CLINICAL PHARMACOLOGY: Antisecretory Activity: Acid Secretion ). This is supported by recent clinical trials (see CLINICAL TRIALS: Duodenal Ulcer: Active Duodenal Ulcer ). Therefore, there is no apparent rationale, except for familiarity with use, for treating with anything other than a once-daily at bedtime dosage regimen. In a U.S. dose-ranging study of 400 mg at bedtime, 800 mg at bedtime and 1600 mg at bedtime, a continuous dose-response relationship for ulcer healing was demonstrated.
Side Effects
ADVERSE REACTIONS Adverse effects reported in patients taking cimetidine tablets are described as follows by body system. Incidence figures of 1 in 100 and greater are generally derived from controlled clinical studies. Gastrointestinal Diarrhea (usually mild) has been reported in approximately 1 in 100 patients. CNS Headaches, ranging from mild to severe, have been reported in 3.5% of 924 patients taking 1,600 mg/day, 2.1% of 2,225 patients taking 800 mg/day and 2.3% of 1,897 patients taking placebo. Dizziness and somnolence (usually mild) have been reported in approximately 1 in 100 patients on either 1,600 mg/day or 800 mg/day.
Interactions
Drug Interactions Cimetidine tablets, apparently through an effect on certain microsomal enzyme systems, has been reported to reduce the hepatic metabolism of warfarin-type anticoagulants, phenytoin, propranolol, nifedipine, chlordiazepoxide, diazepam, certain tricyclic antidepressants, lidocaine, theophylline, and metronidazole, thereby delaying elimination and increasing blood levels of these drugs. Clinically significant effects have been reported with the warfarin anticoagulants; therefore, close monitoring of prothrombin time is recommended, and adjustment of the anticoagulant dose may be necessary when cimetidine tablets are administered concomitantly. Interaction with phenytoin, lidocaine, and theophylline has also been reported to produce adverse clinical effects.
Warnings
CONTRAINDICATIONS Cimetidine tablets are contraindicated for patients known to have hypersensitivity to the product.
Pregnancy
Pregnancy Teratogenic Effects. Pregnancy Category B Reproduction studies have been performed in rats, rabbits and mice at doses up to 40 times the normal human dose and have revealed no evidence of impaired fertility or harm to the fetus due to cimetidine tablets. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Storage
HOW SUPPLIED Cimetidine Tablets, USP are available containing 400 mg of cimetidine, USP. The 400 mg tablets are green, film-coated, five-sided, house-shaped, partially scored tablets debossed with M on one side and 372 on the other side. They are available as follows: NDC 51655-697-51 bottles of 40 tablets Store at 20° to 25°C (68° to 77°F).
Frequently Asked Questions
What is Cimetidine used for?▼
INDICATIONS AND USAGE Cimetidine tablets are indicated in: 1. Short-term treatment of active duodenal ulcer. Most patients heal within 4 weeks and there is rarely reason to use cimetidine tablets at full dosage for longer than 6 to 8 weeks (see DOSAGE AND ADMINISTRATION: Duodenal Ulcer ). Concomitant antacids should be given as needed for relief of pain. However, simultaneous administration of cimetidine tablets and antacids is not recommended, since antacids have been reported to interfere with the absorption of cimetidine. 2. Maintenance therapy for duodenal ulcer patients at reduced dosage after healing of active ulcer. Patients have been maintained on continued treatment with cimetidine tablets 400 mg at bedtime for periods of up to 5 years. 3.
What are the side effects of Cimetidine?▼
ADVERSE REACTIONS Adverse effects reported in patients taking cimetidine tablets are described as follows by body system. Incidence figures of 1 in 100 and greater are generally derived from controlled clinical studies. Gastrointestinal Diarrhea (usually mild) has been reported in approximately 1 in 100 patients. CNS Headaches, ranging from mild to severe, have been reported in 3.5% of 924 patients taking 1,600 mg/day, 2.1% of 2,225 patients taking 800 mg/day and 2.3% of 1,897 patients taking placebo. Dizziness and somnolence (usually mild) have been reported in approximately 1 in 100 patients on either 1,600 mg/day or 800 mg/day.
Can I take Cimetidine during pregnancy?▼
Pregnancy Teratogenic Effects. Pregnancy Category B Reproduction studies have been performed in rats, rabbits and mice at doses up to 40 times the normal human dose and have revealed no evidence of impaired fertility or harm to the fetus due to cimetidine tablets. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
What are the important warnings for Cimetidine?▼
CONTRAINDICATIONS Cimetidine tablets are contraindicated for patients known to have hypersensitivity to the product.
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Medical Disclaimer
This drug information is for educational purposes only and should not replace professional medical advice. Drug information is sourced from the FDA National Drug Code Directory and Structured Product Labeling. Always consult with a healthcare provider before starting, stopping, or changing any medication.