Which of the following antiseizure drugs is a prodrug, metabolized to phenobarbital?

Correct Answer: B

Rationale: The correct answer is B: Primidone. Primidone is a prodrug that is metabolized in the liver to phenobarbital, which is the active antiseizure component. This process allows for a more controlled and sustained release of phenobarbital in the body. Phenytoin (A) works by blocking sodium channels, Felbamate (C) works by multiple mechanisms, and Vigabatrin (D) works by increasing GABA levels. These mechanisms are different from Primidone's pathway of being converted into phenobarbital.

Correct Answer: D

Rationale: The correct answer is D because alcohol abuse can lead to various medical complications, including liver failure (choice A), tolerance and physical dependence (choice B), and nerve injury, ataxia, and dementia (choice C). Liver cirrhosis is a well-known consequence of chronic alcohol abuse due to liver damage. Tolerance and physical dependence develop with prolonged alcohol consumption. Nerve injury, ataxia, and dementia can result from alcohol-related vitamin deficiencies and neurotoxic effects. Therefore, all of the choices are common medical complications of alcohol abuse.

Correct Answer: B

Rationale: The correct answer is B: Clozapine. Clozapine is a dibenzodiazepine derivative, specifically a dibenzodiazepine antipsychotic agent. It is known for its efficacy in treating treatment-resistant schizophrenia. Fluphenazine (A) is a phenothiazine antipsychotic, Risperidone (C) is a benzisoxazole antipsychotic, and Droperidol (D) is a butyrophenone antipsychotic. These other options belong to different classes of antipsychotic agents and are not dibenzodiazepine derivatives like Clozapine.

Correct Answer: C

Rationale: The correct answer is C: Mirtazapine. Mirtazapine is known to have significant alpha2-adrenoreceptor antagonism, leading to increased release of norepinephrine and serotonin. This mechanism of action helps improve mood and alleviate depression symptoms. Amitriptyline, Nefazodone, and Doxepin do not have significant alpha2-adrenoreceptor antagonism. Amitriptyline primarily works by inhibiting the reuptake of norepinephrine and serotonin, Nefazodone primarily inhibits serotonin reuptake, and Doxepin primarily blocks histamine receptors.

Correct Answer: B

Rationale: The correct answer is B: Triazolam. Triazolam has a short elimination half-life, around 2-5 hours, due to its rapid metabolism. Quazepam (choice A) has a longer elimination half-life, around 39 hours. Diazepam (choice C) has a longer elimination half-life, around 20-100 hours. Clorazepate (choice D) has a longer elimination half-life, around 36-200 hours. In summary, Triazolam is the correct answer as it has the shortest elimination half-life compared to the other benzodiazepines listed.