An ICU protocol prescribes gentamicin as a single high dose every 24 hours rather than divided doses every 8 hours. The pharmacodynamic properties that justify once-daily aminoglycoside dosing are:

• A Time-dependent killing with a short post-antibiotic effect
• B Concentration-dependent killing with no post-antibiotic effect
• C Concentration-dependent killing with a prolonged post-antibiotic effect ✓
• D Time-dependent killing with prolonged accumulation in renal cortex

Explanation

Aminoglycosides show concentration-dependent killing: higher peak concentrations produce faster and more complete bacterial kill, quantified by the Cmax/MIC ratio. They also exhibit a prolonged post-antibiotic effect, meaning bacterial growth remains suppressed after serum levels fall below the MIC. Together these allow a large once-daily dose that maximizes peak concentration while allowing a drug-free interval that reduces nephrotoxicity from cortical accumulation.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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