A 42-year-old man is diagnosed with diabetes mellitus. He has tried diet and exercise without success. A second-generation sulfonylurea agent is prescribed. Which of the following is the most likely side effect he will experience?

Correct Answer: A

Rationale: Second-generation sulfonylureas (e.g., glimepiride, choice A) cause hypoglycemia by stimulating insulin release, a common side effect. Lactic acidosis (choice B) is Metformin-related, myositis (choice C) and pruritus (choice D) aren't typical. Hypoglycemia requires monitoring.

Correct Answer: D

Rationale: Meperidine is a commonly used opioid analgesic that is often used in detoxification programs due to its ability to help manage withdrawal symptoms. In this case, the patient was undergoing a detoxification program supervised by surgery, and a drug was administered intravenously. Meperidine is a likely choice as it can help alleviate withdrawal symptoms and manage pain during the detoxification process.

Correct Answer: B

Rationale: Darifenacin, a muscarinic receptor antagonist used for urinary tract infections, may enhance the action of vecuronium by reducing the risk of cholinergic side effects, such as bradycardia or bronchoconstriction, associated with muscle relaxants. Gentamicin, Timolol, Latanoprost, and Lovastatin are unlikely to have a significant impact on the action of vecuronium in this context.

Correct Answer: B

Rationale: Benzodiazepines (e.g., diazepam, lorazepam) are CNS depressants used for anxiety, seizures, and insomnia. They exert effects by binding to a specific allosteric site on the GABAa receptor, enhancing GABA's inhibitory action. GABA, the primary inhibitory neurotransmitter, opens chloride (Cl⁻) channels, hyperpolarizing neurons and reducing excitability. Benzodiazepines increase the frequency of channel opening, potentiating this effect, leading to sedation and anxiolysis. Blocking Cl⁻ channels (choice A) would oppose inhibition, contrary to their purpose. Acting as direct agonists (choice C) is incorrect—they don't activate the receptor alone but amplify GABA's action. Antagonizing GABAb receptors (choice D) is irrelevant, as benzodiazepines target GABAa specifically. This potentiation mechanism underlies their therapeutic utility and risks like tolerance. Understanding this is key to distinguishing benzodiazepines from other CNS drugs and managing their clinical use effectively.

Correct Answer: B

Rationale: In this case, the neurologist decided to add a second-generation antiepileptic drug that blocks voltage-gated Na+ and Ca2+ channels and may inhibit the synaptic release of glutamate. Among the choices, Lamotrigine fits this description as it is known to block voltage-gated sodium channels, making it the most likely drug prescribed for the patient.