2.2. CYP2B6 (rs3745274, rs2279343) and CYP3A4 (rs2740574) genotyping

Genomic DNA was isolated from white blood cells using the Gentra Puregene Blood Kit according to the manufacturer's instructions. Reagents for TaqMan drug metabolism genotyping assays for allelic discrimination (Applied Biosystems Genotyping Assays) were used to establish the genetic profile of study participants. The following assays identification numbers were used: C_7817765_60 rs3745274 for CYP2B6, C_1837671_50 rs2740574 for CYP3A4 rs2740574, a custom designed TaqMan assay was performed for CYP2B6 rs2279343. The 7500 Fast Real-Time PCR System (Applied Biosystems) was used to genotype the different SNPs. PCR mixture consisted of a 5 μl TaqMan master mix (2X), 0.5 μl TaqMan drug metabolism genotyping assays mix (20X), and 1 μl of DNA completed to 10 μl with nuclease free water. The PCR run method was as follows: an initial step at 60°C for 30 s, hold stage at 95°C for 10 min followed by 40 cycles: step 1 at 95°C for 15 s and step 2 at 60°C for 1 min supplemented by a read stage at 60°C for 30 s.