Beta Blockers USMLE Step 1 Practice Question
A 65-year-old man with severe COPD taking theophylline presents with nausea, tremor, and insomnia. Vital signs show HR 128 bpm, BP 142/88 mmHg, RR 22, temperature 37.2°C, and SpO2 94% on room air. He started ciprofloxacin three days ago for prostatitis. ECG reveals supraventricular tachycardia. Serum theophylline level is 24 mcg/mL (therapeutic range 10-20). He denies chest pain or dyspnea worsening. Which drug interaction most likely explains his toxicity?
Answer choices
- ARoflumilast
- BMontelukast
- CTiotropium
- DTheophyllineCorrect answer
- EIpratropium
- FCiprofloxacin
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