Ranitidine - Kieran's Medical Notes

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Ranitidine

Indications

peptic ulcer disease (PUD)
gastroesophageal reflux disease (GERD
alongside fexofenadine and other antihistamines for the treatment of skin conditions such as hives
Protection against aspirin-induced GI irritation

Administration/Absorption

Dosage

150 mg twice a day or 300 mg once every twenty four hours, usually at night

Distribution

Mechanism

histamine H₂-receptor antagonist

Competitive antagonist of histamine at the parietal cell H₂ receptor.

Suppress the normal secretion of acid by parietal cells and the meal-stimulated secretion of acid.

Histamine released by ECL cells in the stomach is blocked from binding on parietal cell H₂ receptors, which stimulate acid secretion
Therefore, other substances that promote acid secretion (such as gastrin and acetylcholine) have a reduced effect on parietal cells when the H₂ receptors are blocked.

Like the H₁-antihistamines, the H₂ antagonists are inverse agonists rather than true receptor antagonists.

Excretion

Side effects

confusion and depression, although these are very rare and usually only seen in geriatric patients

Interactions

Contraindications

Comments