TABLE 3.
Probability of target attainment and cumulative fraction of response for various dosing regimens for PK/PD targets of 100% fT > MIC and. 50% fT > 4xMIC (100% fT > 4xMIC for continuous infusion)
| Dosing regimen | PTA OF MIC50 (2.0 mg/L) | PTA OF MIC90 (4.0 mg/L) | PTA OF P.A. breakpoint (16.0 mg/L) | CFR (%) | |||||
|---|---|---|---|---|---|---|---|---|---|
| 100% fT > MIC | 50% fT > 4xMIC | 100% fT > MIC | 50% fT > 4xMIC | 100% fT > MIC | 50% fT > 4xMIC | 100% fT > MIC | 50% fT > 4xMIC | ||
| IA 300 mg/kg/day | q8h | 2.30% | 30.90% | 0.10% | 5.50% | 0% | 0% | 2.00% | 32% |
| q6h | 17.90% | 67.90% | 3.10% | 27.10% | 0% | 0% | 15.70% | 60.90% | |
| IA 400 mg/kg/day | q8h | 3.10% | 37.00% | 0.20% | 7.40% | 0% | 0% | 2.70% | 31.80% |
| q6h | 22.00% | 76.60% | 3.80% | 35.00% | 0% | 0% | 19.30% | 69.30% | |
| EI 300 mg/kg/day | q8h | 40.60% | 100% | 12.50% | 100% | 0% | 8.90% | 40.10% | 96.00% |
| q6h | 76.70% | 100% | 45.60% | 100% | 0.90% | 8.90% | 70.30% | 96.00% | |
| EI 400 mg/kg/day | q8h | 47.90% | 100% | 15.70% | 100% | 0% | 30.20% | 42.70% | 96.60% |
| q6h | 84.00% | 100% | 53.10% | 100% | 1.20% | 30.20% | 78.50% | 96.60% | |
| CI 300 mg/kg/day | 100% | 100% | 100% | 98.70% | 98.70% | 28.30% | 98.70% | 96.30% | |
| CI 400 mg/kg/day | 100% | 100% | 100% | 99.40% | 99.40% | 39.80% | 98.70% | 96.80% | |
Note: IA, intermittent administration; EI, Extended infusion; CI, continuous infusion; % fT > MIC, Percentage of the dosing interval with a free piperacillin concentration above MIC; PTA, probability of target attainment; P.A breakpoint, Pseudomonas aeruginosa breakpoint; CFR, Cumulative fraction of response. q6h + q8h: administration every 6 or 8 h.