Which of the following sympathomimetics is preferable for the treatment of chronic orthostatic hypotension?

Correct Answer: C

Rationale: Rationale: Ephedrine is preferable for chronic orthostatic hypotension because it acts as a sympathomimetic by increasing both norepinephrine and epinephrine release, thus improving blood pressure regulation over time. Epinephrine (A) has a short duration of action and may lead to tachycardia. Norepinephrine (B) primarily acts on alpha receptors, which may cause vasoconstriction and worsen orthostatic hypotension. Salmeterol (D) is a long-acting beta-2 agonist used in asthma, not suitable for orthostatic hypotension.

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: 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.