Which action is part of optimizing antifungal therapy when efficacy depends on the AUC/MIC?

• A. Ignore MIC
• B. Use fixed dosing without monitoring
• C. Only consider Cmax
• D. Adjust dose and interval

Answer: (D)

When efficacy depends on AUC/MIC, the goal is to ensure the drug exposure over time relative to the pathogen’s susceptibility is enough to suppress or kill the organism. The key lever for achieving that is adjusting how much drug you give and how often you give it. By tailoring the dose and dosing interval, you can raise or lower the total exposure (the AUC) so that it matches the target associated with the organism’s MIC, maximizing efficacy while avoiding toxicity.

MIC defines how potent the pathogen is against the drug, so you can’t rely on fixed dosing or ignore the MIC. If you don’t account for MIC, you might underexpose a more resistant organism or overexpose a susceptible one. Likewise, focusing only on Cmax ignores the overall exposure throughout the dosing interval, which is what drives AUC/MIC in this scenario. Thus, the practical way to optimize therapy is to adjust both the dose and the interval to reach the desired AUC in relation to the MIC.