Pirenzepine is used in:
**Core Concept**
Pirenzepine is a selective M1 muscarinic receptor antagonist used in the treatment of peptic ulcers. It works by inhibiting gastric acid secretion through a reduction in the release of gastric acid stimulated by acetylcholine at the M1 receptors of parietal cells.
**Why the Correct Answer is Right**
Pirenzepine selectively blocks the M1 muscarinic receptors in the stomach, reducing the release of gastric acid and providing a protective effect against peptic ulcers. This action is distinct from other anticholinergics that block both M1 and M2 receptors. By targeting only the M1 receptors, pirenzepine minimizes side effects such as dry mouth and constipation. The reduction in gastric acid secretion helps to heal and prevent the recurrence of peptic ulcers.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the primary use of pirenzepine. While it may have some effect on the heart rate, it is not primarily used for this indication.
**Option B:** This option is incorrect because it is not a recognized indication for pirenzepine. The drug is not typically used for the treatment of anxiety disorders.
**Option C:** This option is incorrect because it is not a recognized indication for pirenzepine. The drug is not typically used for the treatment of Parkinson's disease.
**Clinical Pearl / High-Yield Fact**
Pirenzepine is a selective muscarinic receptor antagonist that provides a protective effect against peptic ulcers by reducing gastric acid secretion. This action is distinct from other anticholinergics that block both M1 and M2 receptors.
**Correct Answer:** C. Treatment of peptic ulcers