Characteristics of carbachol include all of the following EXCEPT:

Correct Answer: B

Rationale: The correct answer is B because carbachol causes miosis (pupillary constriction) instead of mydriasis (pupillary dilation). Carbachol stimulates muscarinic receptors causing constriction of the pupil. Choices A, C, and D are incorrect because carbachol does decrease intraocular pressure, exerts both nicotinic and muscarinic effects, and is resistant to acetylcholinesterase, respectively.

Correct Answer: C

Rationale: The correct answer is C because a relatively pure alpha agonist primarily acts on alpha receptors in blood vessels causing vasoconstriction, leading to increased peripheral arterial resistance and reflex bradycardia. This results in an increase in blood pressure and venous return. Since alpha agonists primarily target blood vessels, they do not have a direct effect on blood vessels. Choices A, B, and D are incorrect as they are known effects of alpha agonists.

Correct Answer: B

Rationale: The correct answer is B: Metoprolol. Metoprolol is a beta1-selective antagonist, meaning it selectively blocks beta1-adrenergic receptors. This specificity results in decreased heart rate and contractility without affecting beta2 receptors, which are primarily found in the lungs. Choice A, Propranolol, is a non-selective beta blocker that blocks both beta1 and beta2 receptors. Choice C, Carvedilol, is a non-selective beta blocker with additional alpha-blocking activity. Choice D, Sotalol, is a non-selective beta blocker with Class III antiarrhythmic properties. Therefore, the correct answer is B as it is the only beta1-selective antagonist among the options provided.

Correct Answer: C

Rationale: Thiopental is the correct answer because it is an ultra-short-acting barbiturate with a rapid onset and short duration of action. It is commonly used for induction of anesthesia due to its fast-acting properties. Secobarbital and Amobarbital are short to intermediate-acting barbiturates, while Phenobarbital is a long-acting barbiturate used for seizure control. In summary, Thiopental stands out as the ultra-short-acting option compared to the other choices due to its specific pharmacokinetic profile.

Correct Answer: D

Rationale: Step 1: Identify the adverse effects mentioned in the question: Granulocytopenia, gastrointestinal irritation, gingival hyperplasia, and facial hirsutism. Step 2: Recognize the common side effects associated with each drug. Step 3: Phenytoin is known to cause granulocytopenia, gingival hyperplasia, and facial hirsutism. It can also cause gastrointestinal irritation. Step 4: Eliminate other choices: Phenobarbital is not known to cause these side effects. Carbamazepine does not commonly lead to gingival hyperplasia or facial hirsutism. Valproate does not typically cause these specific adverse effects. Step 5: Therefore, the correct answer is D (Phenytoin) as it matches all the mentioned adverse effects.