Beta-blocking agents have all of the following effects except:

Correct Answer: A

Rationale: The correct answer is A because beta-blocking agents do not affect plasma lipid levels directly. Beta-blockers can decrease HDL levels and increase VLDL levels, which is opposite to choice A. Bronchoconstriction (B) is a common side effect of non-selective beta-blockers due to their action on beta-2 receptors in the lungs. Decrease in aqueous humor production (C) is a therapeutic effect of beta-blockers in treating glaucoma. "Membrane-stabilizing" action (D) refers to the ability of some beta-blockers to block sodium channels in the cardiac muscle, leading to antiarrhythmic effects.

Correct Answer: A

Rationale: The correct answer is A: Tolerance. Benzodiazepines are known to lead to tolerance, meaning that over time, the body requires higher doses to achieve the same effect. This limits their usefulness as long-term treatment options. Atropine-like symptoms (B) are not associated with benzodiazepines. Psychotic episodes (C) and myasthenic syndrome (D) are also not common side effects of benzodiazepines. Therefore, the correct answer is A as tolerance limits the effectiveness of benzodiazepines over time.

Correct Answer: C

Rationale: The correct answer is C: Mu-receptors. Mu-receptors are responsible for euphoria and respiratory depression because they are primarily involved in the analgesic effects and central nervous system depression associated with opioids. Kappa-receptors (choice A) are more related to analgesia and sedation. Delta-receptors (choice B) are also involved in analgesia but to a lesser extent compared to Mu-receptors. Choice D is incorrect as not all opioid receptors are responsible for euphoria and respiratory depression.

Correct Answer: C

Rationale: Certainly! The correct answer is C: Alcohol dehydrogenase. Fomepizole is used in treating methanol and ethylene glycol toxicity by inhibiting alcohol dehydrogenase, preventing the formation of toxic metabolites. This mechanism blocks the conversion of methanol and ethylene glycol into their toxic byproducts, formic acid, and glycolic acid, respectively. Choices A, B, and D are incorrect as fomepizole does not target aldehyde dehydrogenase, acetylcholinesterase, or monoamine oxidase in this context.

Correct Answer: C

Rationale: The correct answer is C: Clozapine. Clozapine is known for its high risk of potentially fatal agranulocytosis, a serious blood disorder. It also carries a risk of seizures at high doses. Haloperidol (A) is associated with extrapyramidal symptoms, not agranulocytosis or seizures. Risperidone (B) is less likely to cause agranulocytosis or seizures compared to clozapine. Chlorpromazine (D) can cause agranulocytosis but is not as well-known for this risk as clozapine.