Table 1.

Multivariable determinants of tacrolimus apparent oral clearance

MDZ model				4β‐OHC model
Determinants	B value	P	R 2	Determinants	B value	P	R 2
All patients (n = 147)			0.569				0.525
CYP3A5 expresser	0.671	<0.001	0.292	CYP3A5 expresser	0.604	<0.001	0.292
MDZ Cl/F	0.337	<0.001	0.103	4β‐OHC/C	0.304	0.002	0.032
Haematocrit	–3.358	<0.001	0.060	Haematocrit	–2.661	<0.001	0.074
Weight (kg)	0.008	<0.001	0.046	Weight (kg)	0.012	<0.001	0.050
Age (years)	–0.008	0.001	0.040	Age (years)	–0.008	0.001	0.061
TAC QD	0.182	0.003	0.029	TAC QD	0.139	0.026	0.017
CYP3A5 non‐expressers (n = 118)			0.437				0.319
MDZ Cl/F	0.423	<0.001	0.220	4β‐OHC/C	0.357	0.002	0.063
Haematocrit	–3.398	<0.001	0.097	Haematocrit	–2.556	<0.001	0.074
Weight (kg)	0.005	0.029	0.024	Weight (kg)	0.012	<0.001	0.083
Age (years)	–0.008	0.002	0.049	Age (years)	–0.008	0.005	0.100
TAC QD	0.190	0.005	0.047	–
CYP3A5 expressers (n = 29)			0.342
Weight (kg)	0.014	0.001	0.247
Age (years)	–0.008	0.045	0.095

Neither MDZ Cl/F nor 4β‐OHC/C explained TAC Cl/F variability in CYP3A5 expressers

4β‐OHC/C, 4β‐hydroxycholesterol/cholesterol; CYP, cytochrome P450; MDZ Cl/F, midazolam apparent oral clearance; QD, once‐daily formulation; TAC, tacrolimus