Which of the following drugs is a nondepolarizing muscle relaxant?

Correct Answer: A

Rationale: The correct answer is A: Pancuronium. It is a nondepolarizing muscle relaxant that works by blocking acetylcholine receptors at the neuromuscular junction, leading to muscle relaxation. Succinylcholine (B) is a depolarizing muscle relaxant that causes initial muscle depolarization before relaxation. Hexamethonium (C) is a ganglionic blocking agent used for hypertension. Scopolamine (D) is an anticholinergic drug used for motion sickness. Thus, the correct choice is A as it specifically acts as a nondepolarizing muscle relaxant by blocking acetylcholine receptors.

Correct Answer: C

Rationale: Rationale: Ephedrine is preferable for chronic orthostatic hypotension because it acts as a sympathomimetic by increasing both norepinephrine and epinephrine release, thus improving blood pressure regulation over time. Epinephrine (A) has a short duration of action and may lead to tachycardia. Norepinephrine (B) primarily acts on alpha receptors, which may cause vasoconstriction and worsen orthostatic hypotension. Salmeterol (D) is a long-acting beta-2 agonist used in asthma, not suitable for orthostatic hypotension.

Correct Answer: C

Rationale: The correct answer is C: Sotalol. Sotalol is a nonselective beta-blocker with no intrinsic sympathomimetic or local anesthetic activity, making it suitable for treating life-threatening ventricular arrhythmias. Propranolol (A) is also a nonselective beta-blocker but has intrinsic sympathomimetic activity. Oxprenolol (B) is nonselective but has partial agonist activity. Atenolol (D) is a selective beta-1 blocker and not suitable for ventricular arrhythmias.

Correct Answer: C

Rationale: The correct answer is C, Zaleplon. Zaleplon is a non-benzodiazepine hypnotic agent that acts primarily on the GABA receptors to induce sleep without significant muscle relaxing or anticonvulsant effects. Flurazepam (A) and Triazolam (B) are benzodiazepines that have muscle relaxing and anticonvulsant properties, making them less ideal for pure hypnotic effects. "None of the above" (D) is incorrect as Zaleplon fits the criteria specified in the question.

Correct Answer: B

Rationale: The correct answer is B: Diazepam. Diazepam is the most commonly used drug for the acute treatment of seizure clusters due to its rapid onset of action and efficacy in stopping seizures quickly. It is a benzodiazepine that acts by enhancing the effects of GABA, an inhibitory neurotransmitter. Valproate (A) is used for long-term seizure management, not acute seizure clusters. Phenytoin (C) is also used for long-term seizure control and has a slower onset of action. Gabapentin (D) is not typically used for acute seizure treatment as it is more commonly used for chronic pain or neuropathic conditions.