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Table 2 Main pharmacokinetic parameters of three drugs described by their name (overt) or as placebo (covert)

From: Does the placebo effect modulate drug bioavailability? Randomized cross-over studies of three drugs

  Cephalexin Ibuprofen Paracetamol
Parameter Overt Covert P value Overt Covert P value Overt Covert P value
AUCT (μg.hr./ml) 68.53 ± 26.39 67.20 ± 24.96 0.47 104.38 ± 20.08 101.43 ± 21.82 0.27 18.48 ± 3.98 18.52 ± 3.68 0.62
AUCI (μg.hr./ml) 71.11 ± 28.04 69.61 ± 25.77 0.46 109.40 ± 20.45 109.65 ± 21.54 0.99 19.04 ± 4.11 19.07 ± 3.79 0.65
Cmax (μg/ml) 40.16 ± 16.51 39.32 ± 17.01 0.68 31.97 ± 6.53 29.17 ± 10.34 0.08 5.72 ± 1.74 6.08 ± 1.62 0.16
Tmax (hr) 1.11 ± 0.42 1.09 ± 0.49 0.82 1.86 ± 0.90 2.02 ± 1.21 0.58 1.01 ± 0.66 0.94 ± 0.62 0.45
λ (hr −1) 0.68 ± 0.15 0.67 ± 0.13 0.99 0.39 ± 0.06 0.35 ± 0.08 0.052 0.30 ± 0.05 0.30 ± 0.05 0.51
t½ (hr) 1.07 ± 0.23 1.07 ± 0.23 0.99 1.85 ± 0.53 2.11 ± 0.74 0.052 2.33 ± 0.35 2.35 ± 0.35 0.51
Cmax/AUCI (hr −1) 0.57 ± 0.12 0.56 ± 0.12 0.86 0.30 ± 0.05 0.27 ± 0.08 0.06 0.30 ± 0.07 0.33 ± 0.10 0.14
AUCT/AUCI 0.97 ± 0.02 0.97 ± 0.02 0.84 0.95 ± 0.05 0.93 ± 0.08 0.10 0.97 ± 0.01 0.97 ± 0.02 0.74
AUCOverttmax (μg.hr./ml) 17.87 ± 10.91 19.98 ± 15.56 0.73 22.65 ± 9.84 24.69 ± 25.77 0.04 2.51 ± 2.11 3.02 ± 2.90 0.10
  1. Data are unadjusted mean±SD of untransformed values. AUCT is area-under-the-plasma-concentration-time curve from time 0 to last measured concentration. AUCI is area-under-the-plasma-concentration-time curve extrapolated to infinity. Cmax and Tmax are first measured maximum plasma level and its time, respectively. λ is terminal elimination constant. t½ is plasma half-life. AUCOverttmax is area-under-the-plasma-concentration-time curve to Tmax under overt drug administration. P values were obtained from Analysis of variance (ANOVA) of natural logarithm-transformed values except for Tmax.