Which of the following drugs is a nonselective beta-blocker without intrinsic sympathomimetic or local anesthetic activity and used for the treatment of life-threatening ventricular arrhythmias?

Correct Answer: C

Rationale: The correct answer is C: Sotalol. Sotalol is a nonselective beta-blocker with no intrinsic sympathomimetic or local anesthetic activity, making it suitable for treating life-threatening ventricular arrhythmias. Propranolol (A) is also a nonselective beta-blocker but has intrinsic sympathomimetic activity. Oxprenolol (B) is nonselective but has partial agonist activity. Atenolol (D) is a selective beta-1 blocker and not suitable for ventricular arrhythmias.

Correct Answer: B

Rationale: The correct answer is B: Diazepam. Diazepam is the most commonly used drug for the acute treatment of seizure clusters due to its rapid onset of action and efficacy in stopping seizures quickly. It is a benzodiazepine that acts by enhancing the effects of GABA, an inhibitory neurotransmitter. Valproate (A) is used for long-term seizure management, not acute seizure clusters. Phenytoin (C) is also used for long-term seizure control and has a slower onset of action. Gabapentin (D) is not typically used for acute seizure treatment as it is more commonly used for chronic pain or neuropathic conditions.

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.