Which of the following antiseizure drugs acts directly on the GABA receptor-chloride channel complex?

Correct Answer: B

Rationale: Step-by-step rationale: 1. Diazepam is a benzodiazepine that enhances GABAergic transmission by binding to GABA-A receptors. 2. GABA-A receptors are chloride channels that open in response to GABA binding. 3. By binding to GABA-A receptors, diazepam increases chloride influx, leading to neuronal hyperpolarization and inhibition of seizure activity. Summary: A. Vigabatrin inhibits GABA transaminase, increasing GABA levels indirectly. C. Gabapentin modulates calcium channels and has no direct effect on GABA receptors. D. Valproate increases GABA levels but does not directly bind to GABA receptors.

Correct Answer: B

Rationale: Certainly! Fomepizol is the correct antidote for ethylene glycol and methanol poisoning as it inhibits the enzyme alcohol dehydrogenase, preventing the conversion of these toxic alcohols into their more harmful metabolites. Disulfiram (A) is used in alcohol aversion therapy, not for poisoning treatment. Naltrexone (C) is an opioid receptor antagonist used in alcohol dependence, not poisoning. Amphetamine (D) is a stimulant drug, not an antidote for poisoning. Thus, B is the correct choice for treating ethylene glycol and methanol poisonings.

Correct Answer: A

Rationale: Rationale: A: Correct. Clozapine has potent anticholinergic activity, leading to side effects like dry mouth and constipation. B: Incorrect. Clozapine has higher affinity for serotonin receptors than D1 and D2 dopamine receptors. C: Incorrect. Clozapine is known for low extrapyramidal side effects compared to typical antipsychotics. D: Incorrect. Clozapine is an atypical antipsychotic, not related to typical antipsychotic agents.

Correct Answer: B

Rationale: The correct answer is B: Eleuterococci extract. Adaptogens are substances that help the body adapt to stress and promote balance. Eleutherococcus, also known as Siberian ginseng, is a well-known adaptogen commonly used as a stimulant in traditional medicine. Rationale: 1. Eleuterococci extract is a known adaptogen that helps the body cope with stress and fatigue. 2. Amphetamine and Sydnocarb are stimulant drugs but do not belong to the category of adaptogens. 3. Caffeine is a stimulant but does not qualify as a true adaptogen since it does not have the holistic stress-adapting properties of adaptogens. In summary, Eleuterococci extract is the correct choice as it aligns with the definition and properties of adaptogens, while the other choices lack the specific stress-adapting qualities required for adaptogens.

Correct Answer: A

Rationale: Rationale: 1. Buspirone is a non-benzodiazepine anxiolytic that acts on serotonin receptors, not GABA receptors like other sedative-hypnotic drugs. 2. Since it does not target GABA receptors, it does not potentiate CNS depressant effects of ethanol, phenothiazines, or tricyclic antidepressants. 3. This makes it the only drug in the list that does not interact with these substances, making it the correct answer. Summary: - Phenobarbital, Diazepam, and Chloralhydrate are sedative-hypnotic drugs that potentiate CNS depressant effects of ethanol and other drugs due to their action on GABA receptors. - Buspirone, on the other hand, does not potentiate these effects as it acts on serotonin receptors, not GABA receptors.