Characteristics of reserpine include all of the following EXCEPT:

Correct Answer: C

Rationale: The correct answer is C because reserpine actually causes a sympatholytic effect, not a sympathomimetic effect. Reserpine depletes norepinephrine and serotonin stores in the brain, leading to decreased sympathetic activity. Choices A, B, and D are incorrect because reserpine does inhibit the uptake of norepinephrine, decrease cardiac output and peripheral resistance, and deplete catecholamines and serotonin stores in the brain, respectively.

Correct Answer: A

Rationale: The correct answer is A: TRUE. In Parkinson's disease, there is a reduction in dopamine levels in the basal ganglia, leading to the characteristic motor symptoms. This is due to the degeneration of dopamine-producing neurons in the substantia nigra. Choice B is incorrect because the statement is true. Choice C (None) and D (All) are incorrect as they do not provide any meaningful explanation.

Correct Answer: D

Rationale: The correct answer is D because fentanyl can produce significant respiratory depression by inhibiting brain stem respiratory mechanisms (choice A) and by causing truncal rigidity (choice C). Inhibiting brain stem respiratory mechanisms affects the control of breathing, leading to decreased respiratory rate and depth. Truncal rigidity can impair chest wall movement, further reducing respiratory function. Choice B, suppression of the cough reflex leading to airway obstruction, is incorrect as it does not directly relate to respiratory depression caused by fentanyl.

Correct Answer: C

Rationale: Step-by-step rationale for choice C (Analgin) being the correct answer for possible adverse effect of Methemoglobinemia: 1. Analgin contains metamizole, which can lead to methemoglobinemia by causing the oxidation of hemoglobin. 2. Methemoglobinemia is a condition where hemoglobin is unable to transport oxygen efficiently. 3. Aspirin (choice A), Paracetamol (choice B), and Ketorolac (choice D) do not typically cause methemoglobinemia. Summary: - Choice A (Aspirin) is incorrect because it does not cause methemoglobinemia. - Choice B (Paracetamol) is incorrect because it does not cause methemoglobinemia. - Choice D (Ketorolac) is incorrect because it does not cause methemoglobinemia. - Choice C (Analgin) is correct due to its potential to cause methemoglobinemia through the presence of metamizole.

Correct Answer: D

Rationale: The correct answer is D: Phenelzine. Phenelzine is an irreversible MAO inhibitor that irreversibly binds to and inhibits monoamine oxidase enzymes. This irreversible binding leads to a long-lasting inhibition of MAO activity. Moclobemide (A) is a reversible MAO inhibitor, while Selegiline (B) is a selective irreversible MAO-B inhibitor. Tranylcypramine (C) is a reversible MAO inhibitor. Therefore, Phenelzine is the only irreversible MAO inhibitor among the options provided.