TABLE 2.

Effect of rifampin on the pharmacokinetics of caspofungina

Study, day, and caspofungin PK parameterCaspofungin coadministered with rifampinCaspofungin administered aloneGeometric mean ratio (90% CI)b
nGeometric meannGeometric mean
Study A
    Day 1
        AUC0-24 (μg · h/mL)1090.441056.071.61 (1.46, 1.79)
        C1h (μg/ml)107.87107.611.03 (0.95, 1.12)
        C24h (μg/ml)101.91100.712.70 (2.20, 3.31)
    Day 14
        AUC0-24 (μg · h/ml)1093.351083.171.12 (0.97, 1.30)
        C1h (μg/ml)9c9.05108.861.02 (0.92, 1.13)
        C24h (μg/ml)101.30101.500.86 (0.65, 1.14)
Study B
    Day 1
        AUC0-24 (μg · h/ml)1475.081269.051.09 (0.99, 1.20)
        C1h (μg/ml)148.43128.760.96 (0.89, 1.04)
        C24h (μg/ml)140.76121.070.71 (0.58, 0.87)
    Day 14
        AUC0-24 (μg · h/ml)1497.891297.141.01 (0.91, 1.11)
        C1h (μg/ml)149.611210.000.96 (0.87, 1.06)
        C24h (μg/ml)141.24121.790.69 (0.56, 0.85)
  • a Rifampin (600 mg) was administered orally once daily, and caspofungin (50 mg) was administered IV once daily. PK, pharmacokinetics.

  • b Caspofungin plus rifampin/caspofungin alone.

  • c No C1h sample was obtained for one subject.