Which of the following is TRUE regarding the pharmacodynamic killing pattern of aminoglycosides compared to beta-lactams?
- A Aminoglycosides are time-dependent killers; beta-lactams are concentration-dependent
- B Both are time-dependent and require continuous infusion
- C Aminoglycosides are concentration-dependent killers with a post-antibiotic effect; beta-lactams are time-dependent ✓
- D Both exhibit a significant post-antibiotic effect that allows once-daily dosing
Correct answer: C. Aminoglycosides are concentration-dependent killers with a post-antibiotic effect; beta-lactams are time-dependent
Explanation
Aminoglycosides display concentration-dependent killing: higher peak concentrations relative to MIC (Cmax/MIC ratio) drive efficacy. They also exhibit a prolonged post-antibiotic effect (PAE), justifying once-daily dosing. Beta-lactams are time-dependent killers where efficacy depends on the time the free drug concentration remains above the MIC (T>MIC); they have minimal PAE against gram-negatives.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.