Cimetidine tablets block the effects of histamine on receptors located on the basolateral membrane of parietal cells in the stomach, receptors called H2. As a consequence of this blockage, gastric acid secretion decreases with a corresponding reduction in both gastric fluid volume and acidity. Cimetidine also reduces gastric acid secretion in response to other stimuli such as food, caffeine, insulin, betazole, or pentagastrin. Cimetidine does not reduce acid secretion as strongly as proton pump inhibitors (e.g. omeprazole or lansoprazole) because acid secretions respond to multiple stimuli, not all of which are controlled by cimetidine. Cimetidine does not alter gastric motility, gastric emptying, esophageal pressure, or pancreatic and bladder secretions. Cimetidine exhibits a weak anti-androgenic effect.
Cimetidine comes as a tablet and a liquid solution to take by mouth.
It is usually taken 1 time a day at bedtime or 2 to 4 times a day with meals and at bedtime. Without a prescription, it is usually taken 1 or 2 times a day with a glass of water. To avoid symptoms, it is taken 30 minutes before eating or drinking foods that cause heartburn (heartburn). Do not use more or less than the indicated dose, nor more often than prescribed by your doctor. Do not take cimetidine without a prescription for more than 2 weeks unless your doctor tells you to.
If the symptoms of heartburn (heartburn), acid indigestion, or sour stomach last more than 2 weeks, stop taking the medicine and call your doctor.
Oral administration:
Adults and adolescents: 800 mg once a day, at bedtime or 400 mg twice a day or 300 mg four times a day with meals and at bedtime for 8-12 weeks.
Treatments lasting more than 12 weeks are not recommended
Children: Between 20 and 40 mg/kg/day in doses administered every 6 hours
Infants: between 10 and 20 mg/kg/day in doses administered every 6-12 hours
Neonates: between 5 and 10 mg/kg/day in doses administered every 8-12 hours
Intravenous administration (intermittent injection or infusion)
Adults and adolescents: 300 mg IV, diluted appropriately, every 6 hours
Children: 20—40 mg / kg / day IV in divided doses every 6 hours.
Infants: 10-20 mg / kg / day IV in divided doses every 6-12 hours.
Neonates: 5-10 mg / kg / day IV in divided doses every 8-12 hours.
Intramuscular administration
Adults and adolescents: 300 mg IM, undiluted, every 6 hours
Children: 20—40 mg / kg / day im in divided doses every 6 hours.
Infants: 10-20 mg / kg / day im in divided doses every 6-12 hours.
Neonates: 5-10 mg / kg / day im in divided doses every 8-12 hours.
b) Maintenance treatment:
Oral administration
Adults and adolescents: 400 mg once a day at bedtime. The American Association of Gastroenterology suggests maintenance treatment for up to 3 years or more if the underlying disease cannot be reduced (eg, deleted NSAIDs). However, shorter treatments are recommended in the case of symptomatic recurrences of uncomplicated ulcers