 UGT2B7 is also known to be involved in the metabolism of opioids via glucuronidation, and a study investigating the effect of polymorphisms on the analgesic efficacy of buprenorphine found that the mutation C802T significantly worsened the analgesic response to buprenorphine after thoracic surgery, particularly at longer time-points (48 hours) where this long-lasting opioid is meant to remain effective.This same variant was found separately to have significant effects on the blood plasma concentration of valproic acid administered to epilepsy patients, which may account for some of the individual variability seen with this narrow-therapeutic window treatment.Both of these cases indicate decreased concentrations of drug compound probably due to increased glucuronidation activity of UGT2B7 with the C802T polymorphism.