Which of the following neurotransmitters has been most consistently implicated in the patient's disorder?

Correct Answer: A

Rationale: Acetylcholine has been consistently implicated in Alzheimer's disease, which is the disorder the 71-year-old man was diagnosed with. This neurotransmitter is involved in memory and cognitive function, both of which are affected in Alzheimer's disease. A drug that acts on the central cholinergic system would likely target acetylcholine to improve symptoms in this patient. The other neurotransmitters listed are not as strongly linked to Alzheimer's disease.

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: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: The MAC (minimum alveolar concentration) of an inhalational anesthetic is defined as the alveolar concentration at which 50% of patients do not move in response to a surgical stimulus. It is related to the blood/gas partition coefficient of the anesthetic, which determines the rate at which the anesthetic enters and leaves the bloodstream, influencing its potency.

Correct Answer: D

Rationale: The correct answer is D. Increased skeletal muscle tone, fever, skeletal muscle contractions, and diaphoresis are signs of malignant hyperthermia, a rare but life-threatening condition triggered by certain anesthesia agents like halothane and succinylcholine in susceptible individuals. This condition can lead to severe metabolic and respiratory acidosis, cardiac arrhythmias, and hyperkalemia.