Aminoglycosides exhibit concentration-dependent bactericidal killing and a significant post-antibiotic effect (PAE). This pharmacodynamic property best supports which dosing strategy?
- A Once-daily dosing with a higher peak to maximise the Cmax/MIC ratio while allowing drug-free intervals for toxicity reduction ✓
- B Continuous infusion to maintain concentrations above MIC throughout the dosing interval
- C Every 6-hour dosing to keep trough levels high for time-dependent killing
- D Lower doses at more frequent intervals to reduce nephrotoxicity while maintaining bactericidal activity
Correct answer: A. Once-daily dosing with a higher peak to maximise the Cmax/MIC ratio while allowing drug-free intervals for toxicity reduction
Explanation
Aminoglycoside killing is concentration-dependent: efficacy correlates with the peak/MIC ratio (Cmax/MIC target >8–10). The prolonged PAE (continued bacterial suppression after levels fall below MIC) allows once-daily (extended-interval) dosing—a high peak achieves maximal kill, and the drug-free trough period actually reduces renal proximal tubular and cochlear accumulation, thereby decreasing nephrotoxicity and ototoxicity compared with multiple daily doses. Time-dependent killing (continuous infusion strategy) applies to beta-lactams.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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