A 21-year-old male has recently begun pimozide therapy for Tourette's disorder. His parents bring him to the emergency department. They describe that he has been having “different appearing tics” than before, such as prolonged contraction of the facial muscles. While being examined, he experiences opsichotomus (type of extrapyramidal spasm of the body in which the head and heels are bent backward and the body is bowed forward). Which of the following drugs would be beneficial in reducing these symptoms?

Correct Answer: A

Rationale: Benztropine, an anticholinergic agent, is used to treat extrapyramidal symptoms like dystonia caused by antipsychotic medications.

Correct Answer: D

Rationale: Chloral hydrate (choice D) is metabolized to trichloroethanol, which depresses the CNS, inducing sedation. Morphine (choice A) metabolizes to active compounds like morphine-6-glucuronide, not trichloroethanol. Clorazepate (choice B) becomes desmethyldiazepam, a benzodiazepine. Phenobarbitone (choice C) is a barbiturate, not metabolized to trichloroethanol. This identifies Chloral hydrate's metabolic pathway, key for its hypnotic use.

Correct Answer: A

Rationale: β\(_2\)-adrenergic receptors are G-protein-coupled receptors that have seven transmembrane domains, which is a characteristic feature of this receptor family.

Correct Answer: A

Rationale: Newer antiepileptic drugs like ethosuximide and valproate are effective in treating absence seizures which are generalized brief and involve loss of consciousness.

Correct Answer: D

Rationale: Local anesthetics prevent depolarization by blocking sodium channels leading to nerve impulse inhibition.