Indicate a selective inhibitor of monoamine oxidase B:

Correct Answer: D

Rationale: The correct answer is D: Selegiline. Selegiline is a selective inhibitor of monoamine oxidase B (MAO-B), which helps increase dopamine levels in the brain. Levodopa is a precursor to dopamine, Amantadine is an antiviral drug used to treat Parkinson's symptoms, and Tolcapone is a COMT inhibitor. Selegiline specifically targets MAO-B without affecting MAO-A, making it the most suitable choice for selective inhibition of MAO-B in the context of Parkinson's disease treatment.

Correct Answer: D

Rationale: The correct answer is D: Thiothixene. Thiothixene is a thioxanthene derivative due to its chemical structure containing a thioxanthene ring system. Haloperidol, Clozapine, and Chlorpromazine are not thioxanthene derivatives. Haloperidol is a butyrophenone, Clozapine is a dibenzodiazepine, and Chlorpromazine is a phenothiazine. Therefore, the correct choice is D as it is the only antipsychotic drug among the options that belongs to the thioxanthene class based on its chemical structure.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Tricyclic and heterocyclic antidepressants like trazodone, bupropion, and mirtazapine have fewer antimuscarinic effects compared to older tricyclic antidepressants. These newer antidepressants have a more selective mechanism of action, targeting specific neurotransmitters, which leads to reduced antimuscarinic side effects like dry mouth, constipation, and blurred vision. Therefore, all three options have minimal antimuscarinic effects, making them favorable choices for patients who are sensitive to these side effects.

Correct Answer: B

Rationale: The correct answer is B: Clordiazepoxide. Benzodiazepines are a class of anxiolytic drugs known for their sedative and anxiolytic properties. Clordiazepoxide is a benzodiazepine derivative due to its chemical structure containing a benzene ring fused to a diazepine ring. This structure is characteristic of benzodiazepines and is responsible for their pharmacological effects. A: Buspirone is a non-benzodiazepine anxiolytic that works through a different mechanism by acting as a partial agonist at serotonin receptors. C: Meprobamate is a sedative-hypnotic drug that is structurally unrelated to benzodiazepines. D: Chloral hydrate is a sedative-hypnotic drug with a different chemical structure and mechanism of action compared to benzodiazepines.

Correct Answer: B

Rationale: The correct answer is B: Reddening of the conjunctiva. Cannabis intoxication often causes redness in the eyes due to vasodilation. This occurs because cannabis can lower blood pressure and increase blood flow to the eyes. This physiologic sign, known as "red eye," is a common characteristic of cannabis intoxication. Bradycardia (A) is not typically associated with cannabis use, as it can actually increase heart rate. Miosis (C) refers to constriction of the pupils, which is more commonly seen with opioid use. Nausea and vomiting (D) are possible side effects of cannabis use, but they are not as specific to cannabis intoxication as redness of the conjunctiva.