Cimetidine belongs to the class H2-receptor antagonists, known also as H2-blockers.Updated: Mar 08, 2004 17:47 IST
Systems: Gastro-Intestinal System
Category: H2-receptor antagonist
It is well absorbed orally (60-80 %), but its bioavailablity is reduced by about 1/3 when given with antacids. Theraupetic effect lasts for about 5-8 hours. It is excreted mainly in the urine, within 24 hours,mainly as unchanged drug. It can cross the placental barrier and is secreted in milk.
Cimetidine belongs to the class H2-receptor antagonists, known also as H2-blockers, which are used to treat duodenal ulcers and prevent their recurrence. They are also used to treat gastric ulcers and in some conditions such as Zollinger-Ellison syndrome.
Routes of Administration and Dosage
ORAL-- Duodenal and gastric ulcers: 800 mgs daily at bed time for 4-8 weeks followed by 400 mgs daily at bedtime.  Zollinger ellison syndrome: 400 mgs four times a day.  Stress ulcer prevention:200-400 mgs orally every 4-6 hrs. IV-- In pathological hypersecretary conditions and intractable ulcers in hospitalized patients: 200 mgs slow IV injection given over 2 mins, may be repeated 4 to 6 hourly.
H2-blockers are contraindicated in patients with hypersensitivity.
Allergies to Cimetidine can occur. Precaution during Breast-feeding : Cimeitidine passes into the breast milk and may cause adverse effects in the nursing baby. In Adults : Confusion and dizziness may be occur.
Aminophylline, Anticoagulants, Caffeine, Metoprolol, Oxtriphylline, Phenytoin, Propranolol, Theophylline, Tricyclic antidepressants (amitriptyline, amoxapine, clomipramine, desipramine, doxepin, imipramine, nortriptyline, protriptyline ) : these drugs when used with Cimetidine has been shown to greatly potentiate the effects of Cimetidine.H2-blockers may decrease the effects of itraconazole and ketoconazole, hence H2-blockers should be taken at least 2 hours after these drugs.
Cimetidine-CHC (Cadila Healthcare), Cimetiget (Franco-Indian), Cimetin (PCI), Lock-2 (Cadila Healthcare), Tymidin (SPPL), Ulciban (Torrent).
First Published: Mar 08, 2004 17:47 IST