A 70-year-old man with stage 4 chronic kidney disease needs antibiotic cover for a cellulitis likely caused by MRSA and atypical organisms. Which tetracycline can be prescribed without dose adjustment despite his renal failure?
- A Tetracycline
- B Doxycycline ✓
- C Demeclocycline
- D Minocycline
Correct answer: B. Doxycycline
Explanation
Doxycycline is uniquely cleared by nonrenal routes, mainly fecal excretion after biliary secretion and intestinal inactivation, so no dose reduction is required in renal failure. Older tetracyclines accumulate in renal impairment and worsen azotemia by their antianabolic effect, making them contraindicated. Minocycline is largely hepatically cleared but accumulates to a clinically relevant degree and causes vestibular effects, so doxycycline remains the standard safe choice in Indian exam convention.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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