Which agent exerts hypnotic activity with minimal muscle relaxing and anticonvulsant effects?

Correct Answer: C

Rationale: The correct answer is C, Zaleplon. Zaleplon is a non-benzodiazepine hypnotic agent that acts primarily on the GABA receptors to induce sleep without significant muscle relaxing or anticonvulsant effects. Flurazepam (A) and Triazolam (B) are benzodiazepines that have muscle relaxing and anticonvulsant properties, making them less ideal for pure hypnotic effects. "None of the above" (D) is incorrect as Zaleplon fits the criteria specified in the question.

Correct Answer: B

Rationale: The correct answer is B: Pentazocine. Pentazocine is a mixed opioid receptor agonist-antagonist, acting as a partial agonist at the mu receptor and antagonist at the kappa receptor. This dual mechanism provides analgesia with less risk of respiratory depression compared to full mu agonists like Fentanyl, Codeine, and Methadone. Fentanyl (A) is a potent mu agonist, Codeine (C) is a prodrug that is metabolized to morphine, a full mu agonist, and Methadone (D) is a full mu agonist used for opioid addiction treatment. By understanding the pharmacological properties of these drugs, we can determine that Pentazocine is the only correct choice.

Correct Answer: B

Rationale: The correct answer is B: Paracetamol. Paracetamol is a non-narcotic analgesic that lacks anti-inflammatory effects. It works primarily by inhibiting the production of prostaglandins in the brain, which helps to reduce pain and fever. Naloxone (A) is an opioid antagonist used to reverse the effects of opioids. Metamizole (C) and Aspirin (D) are both non-narcotic analgesics but have anti-inflammatory effects unlike Paracetamol.

Correct Answer: D

Rationale: The correct answer is D, Fluoxetine. Second-generation heterocyclic drugs refer to selective serotonin reuptake inhibitors (SSRIs), which include fluoxetine. SSRIs are considered second-generation due to their improved safety and tolerability compared to first-generation heterocyclic drugs like tricyclic antidepressants (e.g., imipramine and maprotiline). Phenelzine is a monoamine oxidase inhibitor (MAOI), not a heterocyclic drug. Imipramine and maprotiline are tricyclic antidepressants, falling under the first-generation category. Therefore, the correct choice is D as it fits the criteria for a second-generation heterocyclic drug.

Correct Answer: A

Rationale: Step-by-step rationale for the correct answer (A): Sydnocarb is a stimulant drug known to decrease fatigue, enhance professional work performance, and combat drowsiness. This aligns with the statement in choice A. The drug does not induce feelings of prosperity, relaxation, or euphoria (choice B), as it is not a psychoactive substance. Sydnocarb does not cause an influx of physical and mental forces or excitation of locomotive and speech (choice C), as it primarily targets fatigue and alertness. Additionally, Sydnocarb does not exhibit peripheral sympathomimetic action (choice D), which involves mimicking the effects of the sympathetic nervous system on peripheral organs.