Which of the following opioid analgesics is used in obstetric labor?

Correct Answer: C

Rationale: The correct answer is C: Meperidine. Meperidine is commonly used in obstetric labor due to its rapid onset of action and short duration, making it suitable for managing acute pain during labor without affecting the fetus adversely. Fentanyl (A) is also a potent opioid analgesic, but its rapid onset and short duration make it more suitable for surgical procedures. Pentazocine (B) is a partial opioid agonist-antagonist and is not commonly used in obstetric labor due to its limited efficacy in managing severe pain. Buprenorphine (D) is a partial agonist with a long duration of action and is typically used for opioid maintenance therapy rather than acute pain management during labor.

Correct Answer: A

Rationale: Rationale: MAO-A is more selective for depression because it primarily metabolizes serotonin and norepinephrine, neurotransmitters implicated in mood regulation. MAO-B mainly metabolizes dopamine. Choices B and C are incorrect because MAO-B is not as closely associated with depression, and MAO-C is a fictitious enzyme.

Correct Answer: D

Rationale: The correct answer is D. Camphor is not a respiratory or cardiac analeptic. Cordiamine, Bemegride, and Caffeine are all known to have stimulant effects on the respiratory and cardiac systems. Cordiamine and Bemegride specifically act as central nervous system stimulants, while Caffeine is a known respiratory and cardiac stimulant. Camphor, on the other hand, is commonly used in topical products for its cooling and soothing effects and does not have any direct stimulant effects on the respiratory or cardiac systems. Therefore, D is the correct answer as it does not belong to the category of respiratory and cardiac analeptics.

Correct Answer: C

Rationale: Rationale: Diazepam belongs to strong euphorizing agents due to its ability to produce feelings of euphoria and relaxation. It is a benzodiazepine with potent anxiolytic and sedative properties. Mebicarum (A) is an anxiolytic, not a strong euphorizer. Buspirone (B) is an anxiolytic without strong euphorizing effects. Chlordiazepoxide (D) is also a benzodiazepine but is not known for strong euphorizing properties.

Correct Answer: B

Rationale: The correct answer is B: Derivatives of Ipecacuanha and Thermopsis. These substances stimulate the reflex mechanism of coughing, leading to increased mucus clearance from the airways. Mucolytics like Ambroxol (choice D) thin out mucus, while sodium benzoate (choice A) is a preservative and trypsin (choice C) is an enzyme and not an expectorant. Therefore, B is correct as it directly promotes the cough reflex for mucus expulsion.