Which of the following sympathomimetics is a beta2-selective agonist?

Correct Answer: A

Rationale: Rationale: Terbutaline is a beta2-selective agonist because it primarily targets beta2-adrenergic receptors in the lungs, leading to bronchodilation. Xylometazoline is an alpha-adrenergic agonist, Isoproterenol is a non-selective beta agonist, and Dobutamine primarily targets beta1-adrenergic receptors. Therefore, Terbutaline is the correct choice for beta2-selective agonist based on its pharmacological action.

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: A

Rationale: The correct answer is A: Gastrointestinal reactions, such as anorexia, pain, nausea, and vomiting. Ethosuximide is primarily used to treat absence seizures. Its common side effects include gastrointestinal reactions due to its irritant effect on the gastric mucosa. Anorexia, pain, nausea, and vomiting are commonly reported adverse effects. Exacerbated grand mal epilepsy (choice B) is not a known adverse effect of ethosuximide. Transient lethargy or fatigue (choice C) is a common side effect, but it is not dose-related. Therefore, the correct answer is A, as it accurately reflects the dose-related adverse effect of ethosuximide, while the other choices do not.

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.