Antimicrobials USMLE Step 1 Practice Question
A 55-year-old man with newly diagnosed pulmonary tuberculosis (chest X-ray showing left upper lobe infiltrate) is started on isoniazid, rifampin, pyrazinamide, and ethambutol. Two weeks later, he presents with progressive painful peripheral neuropathy affecting his feet and hands. Vital signs: BP 128/82, HR 92, RR 16, Temp 37.2°C, SpO2 98% on room air. Serum vitamin B6 level is low. He denies visual changes. Which agent is responsible, and what intervention is recommended?
Answer choices
- AIsoniazid-induced deficiency; add pyridoxine (vitamin B6)Correct answer
- BPyrazinamide hyperuricemia; increase hydration
- CDrug-drug interaction; switch to alternative regimen
- DRifampin hepatotoxicity; check liver function tests
- EEthambutol-induced optic neuritis; discontinue the drug
- FEthambutol-induced deficiency; add thiamine (vitamin B1)
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