High levels of several antipsychotics and antidepressants due to a pharmacogenetic cause: a case report.

Pharmacogenetic analysis to explain or predict the response of a specific patient to drug therapy is increasingly used in clinical practice. This holds especially true for CYP genotyping in psychiatry. We present a patient with genetic polymorphisms in more than one CYP450 enzyme, resulting in reduced effectiveness of CYP enzymes, explaining the high drug serum trough levels of antipsychotics and antidepressants and difficulty in optimizing therapy and dosing. Mrs X was found to be a CYP1A2, CYP2D6, CYP3A4 intermediate and in addition a CYP2C19 poor metabolizer. For Mrs X, pharmacogenetic analysis has contributed to reconsider choice and use of medication. Prior knowledge of the genetic polymorphisms in this patient might have avoided treatment delay and discomfort.