Which of the following drugs is both a muscarinic and nicotinic blocker?

Correct Answer: B

Rationale: Benztropine is the correct answer as it acts as both a muscarinic and nicotinic blocker. Benztropine primarily blocks muscarinic receptors, leading to decreased parasympathetic activity. It also has some nicotinic blocking effects, particularly at higher doses. Atropine (choice A) is a muscarinic antagonist only, while Hexamethonium (choice C) and Succinylcholine (choice D) are nicotinic antagonists only.

Correct Answer: C

Rationale: The correct answer is C because salmeterol does not stimulate heart rate, contractility, or cardiac output. Salmeterol is a long-acting beta2 agonist that primarily acts on the bronchial smooth muscles to provide bronchodilation in conditions like asthma and chronic obstructive pulmonary disease. Choice A is incorrect because salmeterol is indeed a potent selective beta2 agonist. Choice B is also incorrect as salmeterol does not cause uterine relaxation. Choice D is incorrect as salmeterol is commonly used in the therapy of asthma to provide long-term symptom control.

Correct Answer: A

Rationale: Step-by-step rationale for choice A being correct: 1. Metoprolol and atenolol are both selective beta1-adrenergic receptor antagonists. 2. Being beta1-selective means they primarily target beta1 receptors in the heart. 3. This results in decreased heart rate and reduced blood pressure. 4. Choice A is correct as it accurately describes the pharmacological action of metoprolol and atenolol. Summary of why other choices are incorrect: - Choice B (nonselective beta antagonists) is incorrect as metoprolol and atenolol are selective for beta1 receptors. - Choice C (intrinsic sympathomimetic activity) is incorrect as metoprolol and atenolol lack intrinsic sympathomimetic activity. - Choice D (anesthetic action) is incorrect as metoprolol and atenolol do not have anesthetic properties.

Correct Answer: A

Rationale: The correct answer is A: Triazolam. Triazolam has a short half-life, leading to quicker elimination from the body, which can cause a more pronounced "rebound" effect after discontinuation, resulting in rebound insomnia. Flurazepam and Temazepam have longer half-lives, so they are less likely to cause rebound insomnia. Choice D is incorrect as not all benzodiazepines cause rebound insomnia equally.

Correct Answer: B

Rationale: The correct answer is B: Carbamazepine. Carbamazepine is most commonly associated with the development of Steven-Johnson syndrome due to its high risk of causing severe hypersensitivity reactions. This drug has been widely reported to be a major cause of Steven-Johnson syndrome compared to the other options. Phenytoin (choice A) is known for causing different types of skin reactions but is less commonly linked to Steven-Johnson syndrome. Valproate (choice C) and Lamotrigine (choice D) have also been associated with skin reactions, but the incidence of Steven-Johnson syndrome with these drugs is lower compared to Carbamazepine.