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. 2005 Apr;59(4):433–439. doi: 10.1111/j.1365-2125.2004.02323.x

Table 1.

The effect of gemfibrozil on the pharmacokinetics of R-warfarin and S-warfarin in 10 healthy subjects. A single oral dose of 10 mg racemic warfarin was ingested on day 3 of pretreatment with gemfibrozil 600 mg or placebo twice daily for 8 days

Variable Placebo phase Gemfibrozil phase Mean difference between placebo and gemfibrozil phase (95% CI)
R-Warfarin
Cmax (mg l−1) 0.55 ± 0.15 0.52 ± 0.09 −0.03 (−0.10, 0.04)
Percentage of placebo (range) 100 94 (77–136)
tmax (h) 1.5 (1–3) 1.5 (1–4)
t1/2 (h) 47.2 ± 8.3 48.4 ± 6.4 1.2 (−2.2, 4.7)
AUC(0–168) (mg l−1 h) 28.5 ± 6.5 26.5 ± 5.9 −1.9 (−3.5, −0.37)
Percentage of placebo (range) 100 93 (82–104)
AUC(0–∞) (mg l−1 h) 31.3 ± 7.5 29.5 ± 6.9 −1.8 (−3.3, −0.33)
Percentage of placebo (range) 100 94 (85–106)
Vd/F (l kg−1) 0.15 ± 0.02 0.17 ± 0.03 0.02 (−0.00, 0.04)
Cl/F (ml h−1 kg−1) 2.3 ± 0.5 2.5 ± 0.6 0.17 (0.01, 0.33)
S-Warfarin
Cmax (mg l−1) 0.55 ± 0.16 0.51 ± 0.10 −0.05 (−0.12, 0.03)
Percentage of placebo 100 92 (74–134)
tmax (h) 1.0 (1–3) 1.0 (1–4)
t1/2 (h) 40.0 ± 7.6 41.4 ± 6.9 1.4 (−4.0, 6.7)
AUC(0−168) (mg l−1 h) 18.6 ± 4.5 16.4 ± 4.2* −2.3 (−3.6, −0.94)
Percentage of placebo (range) 100 88 (72–105)
AUC(0–∞) (mg l−1 h) 19.9 ± 5.2 17.6 ± 4.7* −2.3 (−3.7, −0.78)
Percentage of placebo (range) 100 89 (70–109)
Vd/F (l kg−1) 0.20 ± 0.02 0.24 ± 0.05 0.04 (0.01, 0.07)
Cl/F (ml h−1 kg−1) 3.6 ± 0.7 4.1 ± 0.9 0.50 (0.09, 0.91)

Data are mean values (± SD); tmax data are given as median and range.

Cmax, Peak plasma concentration; tmax, time to reach Cmax; t1/2, elimination half-life; AUC(0–168), area under the plasma concentration-time curve from 0 to 168 h; AUC(0-∞), area under the plasma concentration-time curve from 0 to infinity; Vd/F, apparent volume of distribution; Cl/F, apparent oral clearance.

*

P < 0.01 vs. placebo phase.

P < 0.05 vs. placebo phase.