Flumazenil blocks the actions of:

Correct Answer: C

Rationale: Flumazenil is a benzodiazepine receptor antagonist that reverses the effects of benzodiazepines like zolpidem, making choice C correct. Flumazenil does not block the actions of phenobarbital (choice A) or morphine (choice B) as they act on different receptors. Ethanol (choice D) is not affected by flumazenil. In summary, flumazenil specifically antagonizes benzodiazepines like zolpidem, making other choices incorrect.

Correct Answer: D

Rationale: The correct answer is D: Trihexyphenidyl. Trihexyphenidyl is an anticholinergic drug that can worsen glaucoma by causing pupil dilation, leading to increased intraocular pressure. This can exacerbate the condition and potentially cause vision problems. Selegiline (A) is a monoamine oxidase inhibitor used in Parkinson's disease but does not affect glaucoma. Levodopa (B) is a gold standard treatment for Parkinson's and does not directly impact glaucoma. Bromocriptine (C) is a dopamine agonist used in Parkinson's but does not have a significant effect on glaucoma. Thus, the correct choice to avoid in patients with glaucoma is Trihexyphenidyl due to its potential to worsen the condition.

Correct Answer: D

Rationale: Alcohol causes an acute increase in the local concentrations of dopamine, opioid, and serotonin. Alcohol consumption leads to the release of dopamine, which is associated with pleasure and reward. It also activates the opioid system, contributing to its addictive properties. Additionally, alcohol affects the serotonin system, influencing mood regulation. Therefore, all of the above choices are correct because alcohol impacts the local concentrations of dopamine, opioid, and serotonin simultaneously.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Orthostatic hypotension can occur due to various mechanisms, such as central action of phenothiazines causing vasodilation, inhibition of norepinephrine uptake leading to decreased vasoconstriction, and alpha adrenoreceptor blockade reducing sympathetic response. Each of these factors can contribute to a drop in blood pressure upon standing. Choices A, B, and C all play a role in the development of orthostatic hypotension, making option D the correct comprehensive answer.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Highly selective serotonin reuptake inhibitors (SSRIs) target the reuptake of serotonin specifically. Sertraline, paroxetine, and fluoxetine are all SSRIs. They do not significantly affect other neurotransmitters, making them highly selective. Therefore, all three choices are correct as they are all examples of highly selective serotonin reuptake inhibitors.