Which statement best describes extended or continuous infusion of beta-lactams?

Which statement best describes extended or continuous infusion of beta-lactams?

• A. It reduces the total daily dose
• B. It maximizes time above MIC during the dosing interval
• C. It primarily increases Cmax/MIC ratio
• D. It shortens the drug half-life

Answer: (B)

The main concept here is that beta-lactam antibiotics are time-dependent killers, so what matters most is how long their concentrations stay above the pathogen’s MIC within a dosing interval. Extended or continuous infusion keeps drug levels above MIC for a longer portion of each interval, increasing the fraction of time the bacteria are exposed to effective concentrations. That sustained exposure enhances bacterial killing and can improve outcomes, especially for pathogens with higher MICs or in patients with serious infections. It doesn’t inherently reduce the total daily dose, and it doesn’t rely on raising the peak level (Cmax) relative to MIC—beta-lactams don’t depend on high peaks. Nor does it change the drug’s intrinsic half-life; it just modifies the exposure profile to maximize time above MIC.

The main concept here is that beta-lactam antibiotics are time-dependent killers, so what matters most is how long their concentrations stay above the pathogen’s MIC within a dosing interval. Extended or continuous infusion keeps drug levels above MIC for a longer portion of each interval, increasing the fraction of time the bacteria are exposed to effective concentrations. That sustained exposure enhances bacterial killing and can improve outcomes, especially for pathogens with higher MICs or in patients with serious infections. It doesn’t inherently reduce the total daily dose, and it doesn’t rely on raising the peak level (Cmax) relative to MIC—beta-lactams don’t depend on high peaks. Nor does it change the drug’s intrinsic half-life; it just modifies the exposure profile to maximize time above MIC.