Drug information of Cimetidine


Drug group:

Cimetidine is in a group of drugs called histamine receptor antagonists. Cimetidine works by decreasing the amount of acid your stomach produces. Cimetidine is used to treat and prevent certain types of ulcer, and to treat conditions that cause the stomach to produce too much acid. Cimetidine is also used to treat gastroesophageal reflux disease (GERD), when stomach acid backs up into the esophagus and causes heartburn.

Mechanism of effect

Cimetidine competitively inhibits the action of histamine at the histamine H2 receptors of the parietal cells and thus is a histamine H2-receptor antagonist. Cimetidine is not an anticholinergic agent.


Cimetidine is a histamine H2-receptor antagonist. It reduces basal and nocturnal gastric acid secretion and a reduction in gastric volume, acidity, and amount of gastric acid released in response to stimuli including food, caffeine, insulin, betazole, or pentagastrin.


Cimetidine is rapidly absorbed after oral administration and peak levels occur in 45–90 minutes. The half-life of Cimetidine is approximately 2 hours. The principal route of excretion of Cimetidine is the urine.


Usual Adult Dose for Duodenal Ulcer Parenteral:
300 mg IV or IM every 6 to 8 hours. Alternatively, a continuous IV infusion may be administered at a rate of 37.5 to 50 mg/hour, or up to a maximum rate of 100 mg/hour (2.4 g/day).
Oral: 800 mg to 1600 mg once a day at bedtime. Alternatively, dosage regimens of 300 mg four times per day, with meals and at bedtime, or 400
mg twice daily, in the morning and at bedtime, have shown to be effective. Usual Adult Dose for Duodenal Ulcer Prophylaxis Parenteral:
300 mg IV or IM once or twice a day. Oral: 400 mg once a day at bedtime.


1-There have been rare reports of transient healing of gastric ulcers despite subsequently documented malignancy. 2-Reversible confusional states have been observed on occasion, predominantly, but not exclusively, in severely ill patients. 3- Advancing age (50 or more years) and preexisting liver and/or renal disease appear to be contributing factors

Points of recommendation

A total of 6 to 8 weeks is usually sufficient for ulcer healing. Gastroesophageal reflux disease usually requires 8 to 12 weeks for healing. Erosive esophagitis therapy generally should not exceed 12 weeks.

Pregnancy level


Related drugs

Ranitidine , Famotidin , Nizatidine

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