Aminoglycosides demonstrate concentration-dependent bactericidal killing and a prolonged post-antibiotic effect (PAE). This supports which dosing strategy?
- A Frequent dosing (every 6 hours) to maintain drug above MIC for most of the dosing interval
- B Continuous infusion to maintain steady drug concentration above MIC throughout the day
- C Extended-interval (once-daily) dosing to maximise the Cmax:MIC ratio and exploit PAE while allowing a trough period that reduces nephrotoxicity ✓
- D Dose is entirely AUC:MIC-driven, making any dosing interval equally effective
Explanation
Aminoglycosides exhibit concentration-dependent killing: efficacy correlates with Cmax/MIC ratio (target ≥8–10). They also have a pronounced post-antibiotic effect (bacteria remain suppressed for 1–4 hours after drug concentrations fall below MIC). Once-daily dosing achieves a high peak concentration for maximum bactericidal effect and exploits PAE. The trough period during once-daily dosing allows cortical accumulation in proximal tubular cells to partially reverse, reducing cumulative nephrotoxicity. Time-dependent antibiotics (beta-lactams) require frequent dosing or continuous infusion.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.