A 55-year-old woman with chronic kidney disease stage 4 requires treatment for scrub typhus. Which tetracycline can be prescribed without dose adjustment because its elimination is predominantly fecal and nonrenal?
- A Tetracycline
- B Doxycycline ✓
- C Oxytetracycline
- D Demeclocycline
Correct answer: B. Doxycycline
Explanation
Doxycycline is excreted mainly in the feces, both unchanged and as inactive chelates, so it does not accumulate in renal failure and is the only tetracycline usable without dose modification in significant kidney disease. Older tetracyclines such as tetracycline, oxytetracycline and demeclocycline depend heavily on urinary excretion and worsen uremia through their antianabolic effect on protein synthesis. This pharmacokinetic property makes doxycycline the standard agent for rickettsial infections in patients with renal impairment.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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