The mechanism of amphetamine action is related to:

Correct Answer: D

Rationale: Step-by-step rationale: 1. Amphetamine acts as a direct catecholaminergic agonist, stimulating the release of norepinephrine and dopamine (A). 2. It also inhibits monoamine oxidase, preventing the breakdown of these neurotransmitters (B). 3. Additionally, amphetamine increases the release of catecholaminergic neurotransmitters by reversing their transporters (C). 4. Therefore, the correct answer is D, as amphetamine's mechanism involves all of the actions mentioned in choices A, B, and C.

Correct Answer: C

Rationale: The correct answer is C: Nitrous oxide. Nitrous oxide inhibits methionine synthase activity by inactivating vitamin B12, leading to megaloblastic anemia. Desflurane, Halothane, and Sevoflurane do not affect methionine synthase or cause megaloblastic anemia. Nitrous oxide is the only anesthetic among the choices known for this specific mechanism of action.

Correct Answer: C

Rationale: Fepranone is the correct answer because it is a medication used to suppress appetite, not stimulate it. Vitamins are essential nutrients, bitters can stimulate appetite, and insulin regulates blood sugar but can also stimulate appetite. Therefore, Fepranone is the only drug in the list that does not stimulate appetite.

Correct Answer: A

Rationale: Step-by-step rationale for why Aminocaproic acid (A) is the correct answer: 1. Aminocaproic acid is a fibrinolytic inhibitor that prevents the breakdown of blood clots. 2. It works by inhibiting the activation of plasminogen to plasmin, which is essential for clot dissolution. 3. Therefore, Aminocaproic acid belongs to the class of fibrinolytic inhibitors. Summary of why the other choices are incorrect: - Ticlopidine (B) is a platelet aggregation inhibitor, not a fibrinolytic inhibitor. - Streptokinase (C) is a fibrinolytic drug that promotes clot breakdown, not an inhibitor. - Vitamin K (D) is essential for clotting factors synthesis, not a fibrinolytic inhibitor.

Correct Answer: B

Rationale: Verapamil is a calcium channel blocker that decreases heart rate by blocking L-type calcium channels in the heart. Choice B, stating it increases heart rate, is incorrect. Verapamil relaxes coronary artery smooth muscle (Choice C) and depresses cardiac contractility (Choice D), making them true statements. So, the correct answer is B as it contradicts the pharmacological effects of verapamil.