Which of the following opioid analgesics can produce an increase in the pulmonary arterial pressure and myocardial work?

Correct Answer: B

Rationale: The correct answer is B: Pentazocine. Pentazocine is a mixed opioid agonist-antagonist that can increase pulmonary arterial pressure and myocardial work due to its kappa agonist activity. Morphine (A) primarily acts on mu-opioid receptors and does not significantly affect pulmonary arterial pressure. Meperidine (C) can cause hypotension rather than an increase in pulmonary arterial pressure. Methadone (D) is a synthetic opioid that has a long duration of action but does not typically cause a significant increase in pulmonary arterial pressure or myocardial work.

Correct Answer: C

Rationale: The correct answer is C: Moclobemide. Moclobemide is a selective short-acting MAO-A inhibitor, which means it specifically targets the MAO-A enzyme, leading to increased levels of serotonin and norepinephrine. This helps alleviate symptoms of depression. Maprotiline (A) is a tetracyclic antidepressant, Amitriptyline (B) is a tricyclic antidepressant, and Selegiline (D) is a MAO-B inhibitor used for Parkinson's disease, not for depression. Therefore, C is the correct answer as it matches the criteria of being a selective short-acting MAO-A inhibitor.

Correct Answer: D

Rationale: The correct answer is D: Significant abuse potential. Cordiamine is primarily used as a cardiac analeptic, respiratory analeptic, and coronarodilatator, meaning it stimulates cardiac and respiratory functions and dilates coronary blood vessels. There is no evidence or indication that cordiamine has significant abuse potential. It is not a psychoactive substance and does not produce euphoria or addiction. Therefore, option D is the correct answer as it does not align with the principal properties of cordiamine.

Correct Answer: B

Rationale: Step 1: Diazepam is a benzodiazepine known for its high abuse potential due to its sedative and hypnotic effects. Step 2: Benzodiazepines like diazepam can lead to physical and psychological dependence. Step 3: Buspirone is a non-benzodiazepine anxiolytic with low abuse potential. Step 4: Phenobarbital is a barbiturate with significant abuse potential but generally less than benzodiazepines. Step 5: Zolpidem is a non-benzodiazepine sedative-hypnotic with lower abuse potential compared to benzodiazepines like diazepam.

Correct Answer: B

Rationale: The correct answer is B: The reflex mechanism. Cytiton acts by triggering a reflex mechanism, which involves a response to a stimulus that is automatic and involuntary. This mechanism is distinct from direct activation of the respiratory center (choice A) or a mixed mechanism (choice C). Choice D is incorrect as Cytiton does have a specific action mechanism. In summary, the correct choice is B because it accurately describes how Cytiton works through a reflex mechanism, while the other choices do not align with the known pharmacological action of Cytiton.