CYP2D6 and neuropathic pain: In a study that elucidated potential genetic factors and covariates affecting the clearance of (+)‐ and (−)‐tramadol in a group of neuropathic pain patients, CYP2B6 *9 was not found to significantly contribute.31 In the present study, the metabolic profiles with the smallest AUCs of the NDT enantiomers belonged to two individuals being CYP2D6 EMs with the CYP2B6 genotype *6/*6 and *5/*5, respectively.