Cimetidine used, Side, Doses, mechanism of action & more

 Cimetidine 

Brand name:- Cimetidine 200mg , 400mg , 800mg tabs, 200mg/2ml injection. , Lock-2 200mg tab.

Cimetidine is a gastric acid reducer used in the short-term treatment of duodenal and gastric ulcers. [1] Therefore, the drug effectively manages gastric hypersecretion and is used to manage reflux esophagitis disease and prevent stress-related gastric ulcers.

Pharmacodynamic:- 

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. It is used to treat gastrointestinal disorders such as gastric or duodenal ulcer, gastroesophageal reflux disease, and pathological hypersecretory conditions. Cimetidine inhibits many of the isoenzymes of the hepatic CYP450 enzyme system. Other actions of Cimetidine include an increase in gastric bacterial flora such as nitrate-reducing organisms.

Mechanism of action:- 

Cimetidine binds to an H2-receptor located on the basolateral membrane of the gastric parietal cell, blocking histamine effects. This competitive inhibition results in reduced gastric acid secretion and a reduction in gastric volume and acidity.

Used:- 

Cimetidine is used to treat ulcers of the stomach and intestines and prevent them from coming back after they have healed. This medication is also used to treat certain stomach and throat (esophagus) problems caused by too much stomach acid (such as Zollinger- Ellison syndrome, erosive esophagitis) or a backward flow of stomach acid into the esophagus (acid reflux disease/GERD). Decreasing extra stomach acid can help relieve symptoms such as stomach pain, heartburn, difficulty swallowing, cough, and trouble sleeping. It can also prevent serious acid damage to your digestive system (such as ulcers, cancer of the esophagus).

Side effects:- 

Headache, dizziness, drowsiness, or diarrhea may occur.

Dose:- 

For ulcer healing — 400mg BD or 800mg at bed time orally; maintenance —400mg at bed time. For stress ulcer — 50mg/ hr i.v. infusion. Rapid or higher dose i.v. injection can causes confusional state, hallucinations, convulsions, bradycardia , arrhythmias, coma or cardiac arrest. As directed by your doctor.