Which of the following drugs most likely caused the patient's disorder?

Correct Answer: A

Rationale: The patient's oversedation and spending the whole day dozing is a common side effect of Zolpidem, which is a sedative-hypnotic drug used for insomnia. Zolpidem is known to cause drowsiness and oversedation, especially in the elderly population. The patient taking a "sleeping pill" from a friend that he couldn't remember the name of is consistent with Zolpidem being the cause of his symptoms.

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: D

Rationale: The correct answer is D because Alzheimer's disease currently has no cure. Step 1: Alzheimer's is a progressive neurodegenerative disease that worsens over time, leading to memory loss (A). Step 2: The exact cause is unknown, with various theories proposed (B). Step 3: Behavioral symptoms like personality changes, wandering, and aggression are common (C). Step 4: There is no cure for Alzheimer's; current treatments aim to manage symptoms and slow progression, not cure the disease (D). The other options are accurate statements related to Alzheimer's disease, making them incorrect choices in this context.

Correct Answer: C

Rationale: Felbamate is primarily metabolized by the CYP1A2 enzyme, making it a suitable choice for patients where CYP1A2 metabolism is desired.

Correct Answer: D

Rationale: The signs and symptoms described in the text, such as talkativeness, mydriasis, muscle twitching, hand tremor, elevated blood pressure, and increased heart rate, are consistent with the effects of amphetamine use. Amphetamine is a stimulant drug that can cause these symptoms by increasing the release of neurotransmitters like dopamine and norepinephrine in the brain. Additionally, the patient being a drug user who tried different drugs supports the likelihood of amphetamine use, as it is commonly abused for its stimulant effects.