Final answer:
Cimetidine is an H₂-receptor antagonist used to reduce stomach acid and treat conditions like ulcers and GERD. It works by blocking receptors in the stomach lining, but can have side effects such as impotence, gynecomastia, and can affect the metabolism of other drugs.
Step-by-step explanation:
Cimetidine is a medication that belongs to a class known as H₂-receptor antagonists. Its mechanism of action (MOA) involves blocking H₂ receptors on the stomach lining which results in decreased production of stomach acid. This medication is commonly indicated for the treatment of ulcers, gastroesophageal reflux disease (GERD), and conditions like Zollinger-Ellison syndrome where excessive stomach acid is produced.
It is also used to treat heartburn associated with acid indigestion and sour stomach. Although generally safe, cimetidine has some possible adverse effects and contra-indications. The drug can lead to impotence and gynecomastia in men due to its antiandrogenic effects and can interact with other medications by affecting liver enzymes responsible for their metabolism. Patients with renal or liver dysfunction should use it cautiously. Other common side effects can include dizziness, headache, and diarrhea.