cimetidine

Question 1

tell about cimetidine

Answer 1

-Cimetidine is a competitive antagonist at parietal cell histamine (H2) receptors, which are the main stimulus for gastric acid secretion.

-It has an imidazole structure and acts to inhibit gastric acid production, raising gastric pH and reducing volume of secretions.

-It can be administered orally (60% bioavailability) or intravenously.

-On rapid intravenous bolus administration it can lead to bradycardia and hypotension.

-It is metabolized in the liver by cytochrome P450 but 50% is excreted renally unchanged.

-In renal failure high plasma levels have been associated with hallucinations, confusion and seizures.

-Cimetidine is an inhibitor of hepatic cytochrome P450 and consequently increases the plasma levels of drugs metabolized by this route, including diazepam, phenytoin and warfarin.

-It has anti-androgen effects, which can cause gynaecomastia, impotence and a drop in sperm count when used in male patients.c