2026 年 9 巻 1 号 p. 366-368
Differences in antibiotic dosing recommendations highlight the tension between maximizing efficacy and ensuring safety. Piperacillin is a striking example, with the Sanford Guide recommending regimens of 13.5-27 g/day based on pharmacokinetic and pharmacodynamic principles aimed at patients who are critically ill, whereas the Japanese package insert advises 2-4 g/day, with a maximum of 16 g/day, reflecting a cautious approach focused on safety in general wards. These divergent strategies reflect distinct philosophies: international guidelines prioritize achieving pharmacokinetic/pharmacodynamic targets to optimize outcomes in patients in intensive care units (ICUs), whereas Japanese labeling emphasizes minimizing adverse events and ecological disruption in broader populations. The clinical consequences of indiscriminate application are significant. High-dose regimens used outside ICU contexts may increase risks of allergy, gastrointestinal disturbance, bone marrow suppression, renal injury, and selection of resistant organisms. Conversely, reliance solely on Japanese recommendations in ICU settings may cause suboptimal exposure and therapeutic failure in severe infections caused by organisms such as Pseudomonas aeruginosa. Awareness of these differences is essential for antimicrobial stewardship. Clinicians should tailor dosing to the clinical context, reserving aggressive regimens for patients who are critically ill or at high risk while maintaining safety-oriented dosing in routine ward practice. By recognizing the underlying philosophies and their intended applications, physicians can avoid inappropriate extrapolation, optimize patient outcomes, and reduce the ecological burden of antibiotic use.
