Which of the following pairs of drugs was most likely administered?

Correct Answer: A

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

Correct Answer: C

Rationale: The correct answer is C. Thiopental's short duration of action is primarily due to its rapid redistribution from the brain to peripheral tissues, leading to a quick recovery. Slow distribution into the CNS, fast elimination, and poor diffusion into central neurons would not explain the short duration of action observed with thiopental.

Correct Answer: A

Rationale: Lidocaine is the most appropriate choice for a 4-day-old boy with methemoglobinemia as it is less likely to cause further methemoglobinemia compared to other local anesthetics. This is important to prevent exacerbating the baby's condition. Lidocaine is considered safe for use in pediatric patients and is commonly used in this population for minor procedures.

Correct Answer: C

Rationale: Lidocaine would be the most appropriate choice for a pregnant woman with a history of anaphylactic reaction to para-aminobenzoic acid (PABA). Lidocaine is an amide local anesthetic that does not contain PABA and is less likely to trigger an allergic reaction in individuals sensitive to this compound. It is important to choose a local anesthetic that is safe for the patient and avoids any potential allergic responses.

Correct Answer: C

Rationale: In a patient with impaired hepatic and renal function, Vecuronium is the most appropriate choice for muscle relaxation as it is primarily eliminated through hepatic metabolism and does not require renal excretion. Succinylcholine is contraindicated in patients with impaired renal function due to the risk of hyperkalemia. Tubocurarine, Mivacurium, and Cisatracurium may have prolonged effects in patients with impaired liver function, making Vecuronium the safest choice in this scenario.