Pharmacogenomics is now beginning to reach clinical practice in neuropsychiatric settings. Currently, guidelines exist to help clinicians in the use of existing genetic information to direct drug selection and/or dosing in the TCA class of antidepressants, carbamazepine, and phenytoin. Additional language in the product labeling suggests that genetic information may also be useful for assessing the starting and target doses and drug interaction potential for a number of other medications such as antidepressants and antipsychotics. Most of the information that has been formally assessed relates to variability in drug-metabolizing enzymes. Variants influencing immune response are notable for influencing the risk for severe dermatological reactions from carbamazepine and phenytoin.
