A 35-year-old woman is brought to the emergency department because of an 18-hour history of severe pain, nausea, vomiting, diarrhea, and anxiety. She was discharged with a pain medication from the hospital 2 weeks ago after treatment of multiple injuries sustained in a motor vehicle collision. She took her last dose 36 hours ago. Her temperature is 36.6°C (97.8°F), pulse is 105/min, respirations are 24/min, and blood pressure is 160/85 mm Hg. Physical examination shows rhinorrhea and piloerection. Bowel sounds are normal. She rates the pain as an 8 on a 10-point scale. Which of the following is the most likely diagnosis?

Correct Answer: C

Rationale: Symptoms (pain, nausea, vomiting, diarrhea, anxiety, tachycardia, hypertension, rhinorrhea, piloerection) 36 hours after stopping pain medication suggest opioid withdrawal, likely oxycodone (F) from her recent hospitalization. Appendicitis causes localized pain and fever, caffeine withdrawal headaches, ethanol withdrawal tremors and seizures, gastric ulcers epigastric pain, and gastroenteritis (E) fever and infection signs—none match this autonomic and piloerection profile.

Correct Answer: D

Rationale: The correct answer is D: An indefinite, prolonged period of time. Adefovir is typically used as a long-term treatment for chronic hepatitis B to suppress the virus and prevent liver damage. Treatment duration is often indefinite as stopping the medication can lead to viral reactivation. Choice A is incorrect as waiting for nephrotoxicity to occur before stopping treatment is not a safe practice. Choice B is incorrect as lifetime treatment is not always necessary. Choice C is incorrect as 48 weeks is not sufficient for chronic hepatitis B treatment.

Correct Answer: B

Rationale: The correct answer is B because the glucocorticoid helps reduce swelling and pain caused by inflammation in otitis externa, while the fluoroquinolone effectively treats the infection. Combining both medications addresses both aspects of the condition, providing comprehensive treatment. Choice A is incorrect because there is no contraindication for using these medications together in this context. Choice C is incorrect as glucocorticoids do not specifically decrease adverse effects of fluoroquinolones. Choice D is also incorrect as glucocorticoids do not directly impact the development of antibiotic resistance to fluoroquinolones.

Correct Answer: E

Rationale: I apologize for the error in the question. However, if we assume the correct answer is meant to be "D: Angina," the rationale is as follows: ACE inhibitors are commonly used to treat angina by dilating blood vessels, reducing blood pressure, and improving blood flow to the heart. Other choices are incorrect because ACE inhibitors are not typically used to treat hyperthyroidism, pulmonary hypertension, or Cushing's syndrome.

Correct Answer: B

Rationale: The correct answer is B: Therapeutic index. The therapeutic index is the ratio between the drug's desired therapeutic effects and its toxic effects. It indicates the margin of safety of a drug. A: Cumulative effect refers to the increased potency or adverse effects of a drug when taken repeatedly. C: Tolerance is the decreasing response to a drug over time, requiring higher doses for the same effect. D: Affinity is the strength of binding between a drug and its target receptor, not directly related to the drug's therapeutic and toxic effects. Therefore, the correct choice is B as it specifically addresses the ratio between therapeutic and toxic effects.