Atropine is used in the treatment of:

Correct Answer: C

Rationale: Atropine is used in the treatment of intestinal colic due to its ability to relax smooth muscles, including those in the gastrointestinal tract. It helps relieve spasms and pain associated with intestinal colic. Tachycardia is usually treated with beta-blockers, not atropine. Glaucoma is treated with medications that reduce intraocular pressure, not atropine. Enlarged prostate is typically managed with medications that target prostate enlargement, not atropine. Therefore, the correct choice is C: Intestinal colic.

Correct Answer: B

Rationale: Step-by-step rationale for why B (Carbachol) is the correct answer: 1. Carbachol is a cholinergic drug that acts on both muscarinic and nicotinic receptors. 2. It is resistant to hydrolysis by both true and pseudo cholinesterase enzymes. 3. Acetylcholine (A) is rapidly hydrolyzed by both cholinesterases. 4. Bethanechol (C) is a muscarinic agonist but not a nicotinic agonist. 5. Succinylcholine (D) is a depolarizing neuromuscular blocking agent, not a cholinergic agonist. Summary: Carbachol is the only drug among the choices that has both muscarinic and nicotinic actions and is resistant to hydrolysis by cholinesterases. Acetylcholine is rapidly hydrolyzed, Bethanechol does not have nicotinic actions, and Succinyl

Correct Answer: D

Rationale: Pilocarpine is a parasympathomimetic agent that stimulates the muscarinic receptors in the eye, causing pupillary constriction and reducing intraocular pressure. This mechanism of action makes it effective in treating glaucoma. Heart failure (A), bronchial asthma (B), and urinary obstruction (C) are not indications for pilocarpine use based on its pharmacological properties and effects.

Correct Answer: D

Rationale: The correct answer is D. Atropine blocks the effects of cholinesterase inhibitors on muscarinic receptors but not on nicotinic receptors, which are responsible for skeletal muscle overstimulation. Atropine can block bronchoconstriction, increased bladder activity, and increased bowel motility as they are mediated by muscarinic receptors. Therefore, the effects on skeletal muscle overstimulation, leading to paralysis, will not be blocked by atropine.

Correct Answer: A

Rationale: The correct answer is A because labetalol is unique among most β-blockers as it also blocks alpha-adrenergic receptors. This dual action results in vasodilation and reduced blood pressure. Choice B is incorrect as labetalol does not cause atropine-like side effects. Choice C is incorrect as labetalol blocks both β1 and β2 receptors. Choice D is also incorrect as labetalol does have some β2 blocking activity, making it not entirely safe for asthmatics.