Toxicology USMLE Step 1 Practice Question
A 67-year-old man with severe COPD presents with vomiting, tremor, and palpitations. Vital signs show HR 128/min, BP 148/92, RR 22/min, temperature 37.2°C, and SpO2 92% on home oxygen. He denies recent respiratory infections. Serum theophylline level is 24 mcg/mL (therapeutic range 10-20). He has taken an older bronchodilator for years. Electrocardiogram shows new supraventricular tachycardia. Which medication is most likely responsible for his acute presentation?
Answer choices
- ATiotropium
- BMontelukast
- CTheophyllineCorrect answer
- DIpratropium
- EOmalizumab
- FAlbuterol
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.