Indicate a muscarinic receptor-blocking drug:

Correct Answer: A

Rationale: The correct answer is A: Scopolamine. Scopolamine is a muscarinic receptor-blocking drug that antagonizes the action of acetylcholine at muscarinic receptors. Scopolamine is commonly used for its anticholinergic effects, such as reducing salivation and mucous secretion. B: Pipecuronium is a neuromuscular blocking agent that acts at the neuromuscular junction, not at muscarinic receptors. C: Trimethaphan is a ganglionic blocker that acts at the autonomic ganglia, not at muscarinic receptors. D: Pilocarpine is a muscarinic receptor agonist, not a muscarinic receptor blocker. It is used to stimulate muscarinic receptors for various therapeutic purposes.

Correct Answer: D

Rationale: The correct answer is D because ephedrine actually increases arterial pressure by stimulating alpha-adrenergic receptors, leading to vasoconstriction. A is incorrect as ephedrine works by directly stimulating adrenergic receptors, not by releasing stored catecholamines. B is correct as ephedrine is indeed a mild CNS stimulant. C is incorrect as tachyphylaxis, or a rapid decrease in response with repeated administration, is not commonly associated with ephedrine.

Correct Answer: B

Rationale: The correct answer is B: Metoprolol. Metoprolol is a cardioselective beta blocker, meaning it primarily targets beta-1 receptors in the heart and has minimal effect on beta-2 receptors in the lungs. This makes it preferable in patients with asthma as it reduces the risk of bronchoconstriction compared to non-selective beta blockers like Propranolol (choice A). Metoprolol also has a lower risk of masking hypoglycemic symptoms in diabetic patients compared to non-selective agents. Nadolol (choice C) and Timolol (choice D) are non-selective beta blockers and may worsen asthma and peripheral vascular diseases due to their effects on beta-2 receptors.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: Rationale: 1. Lacosamide is a sodium channel blocker, working by enhancing slow inactivation of voltage-gated sodium channels. 2. It is used as an adjunctive therapy for partial-onset seizures in adults. 3. Lacosamide is also approved for the treatment of generalized seizures in certain patients. 4. Carbamazepine (A) is a sodium channel blocker but is primarily used for focal seizures. 5. Ethosuximide (C) is a T-type calcium channel blocker used for absence seizures. 6. Lamotrigine (D) is a sodium channel blocker but is mainly used for focal and generalized seizures, not as an adjunctive therapy.