What characterizes drugs with time-dependent killing?

Drugs characterized by time-dependent killing exert their antibacterial effects when their serum concentration remains above the minimum inhibitory concentration (MIC) for a prolonged period. This means that the effectiveness of the drug does not solely depend on achieving a high peak concentration at a single moment but rather on maintaining drug levels above the MIC for a sufficient duration during the dosing interval.

For these types of antibiotics, the time that the drug's concentration remains above the MIC is critical to their efficacy. This principle is especially relevant for certain classes of antibiotics, such as beta-lactams and macrolides, where the duration of exposure is more important than the concentration achieved at any given time.

While it's true that other factors, like half-lives and dosage timing, can influence the overall therapeutic outcome, they are secondary to the primary characteristic that defines time-dependent killing—namely maintaining drug levels above the MIC to ensure bacterial inhibition over time.