520050 research-article2014

ANP0010.1177/0004867413520050Australian & New Zealand Journal of PsychiatryDinama et al.

Letters Australian & New Zealand Journal of Psychiatry 2014, Vol. 48(8) 778­–781

Letters

The role of pharmacogenomic testing in psychiatry: Real world examples Otsile Dinama, Annabelle M Warren and Jayashri Kulkarni Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Australia Corresponding author: Jayashri Kulkarni, Monash Alfred Psychiatry Research Centre, Level 4, 607 St Kilda Road, Melbourne, VIC 3004, Australia. Email: [email protected] DOI: 10.1177/0004867413520050

To the Editor Predicting the efficacy, side effects and optimal psychotropic dose for individual patients is a challenge in psychiatry. Current prescribing patterns follow the maxim ‘start low, go slow’. If patients are unresponsive or adverse effects occur, medication is changed. This is time consuming, inefficient and may lead to prolonged illness and financial strain. Patients may experience a sense of hopelessness, and there may be negative impacts on the therapeutic relationship. Pharmacogenomics is the study of the impact of genes on drug therapy (Krasowski, 2011). Since the 1950s, pharmacogenomics has sought to optimize drug therapy by tailoring medications and doses to the patient’s genetic make-up. The following cases

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describe patients who underwent pharmacogenomic testing using GenesFX Health (Melbourne, Australia) following consultation at the Monash Alfred Psychiatry Research Centre (MAPrc) Women’s Mental Clinic. A 35-year-old single woman, Ms A, was referred to our clinic for a second opinion on the management of ‘agitated depression’. Her depression began following a motorcar accident 8 years prior, after which Ms A experienced panic attacks, flashbacks and several impulsive suicide attempts. She had consulted multiple medical professionals and tried several antidepressants, but she experienced side effects even at small doses. Doctors labelled her as ‘somatizing’, citing her proclivity to side effects ‘abnormal illness behaviour’. Pharmacogenomic testing confirmed that Ms A was highly sensitive to medications. Her results showed slow action of the cytochrome p450 enzyme encoded by the CYP2C19 gene, meaning she was a poor metabolizer of most antidepressants. Ms A was commenced on a small dose of venlafaxine (25 mg BD) and a low-dose short-acting atypical antipsychotic (quetiapine IR, 25 mg/day). Three months later Ms A was much improved. The second case describes a 43-year-old woman, Ms B. She worked long hours as an administrator, living alone with poor social networks. She presented to her GP with a 6-month history of typical depressive symptoms and was prescribed an antidepressant,

but did not improve after 4 months of treatment. Ms B’s pharmacogenomic profile showed increased function of enzymes encoded by CYP2D6 and CYP2C19 genes, meaning she was an ultrarapid metabolizer of most antidepressants. Following the result, Ms B was treated with escitalopram at 30 mg/day, higher than the recommended 20 mg/day. Two months later she felt much better. Pharmacogenomic testing has the potential to aid clinical decision-making and avoid difficulties in usual prescribing practice. There is a need for prospective trials to confirm the economic and clinical benefits (Eichelbaum et al., 2006; Sheffield and Phillimore, 2009). Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

References Eichelbaum M, Ingelman-Sundberg M and Evans WE (2006) Pharmacogenomics and individualized drug therapy. Annual Review of Medicine 57: 119–137. Krasowski AY (2011) Pharmacogenomics. In: South-Paul JE, Matheny SC and Lewis EL (eds) CURRENT Diagnosis & Treatment in Family Medicine, 3rd edition. New York: McGrawHill, pp.531–536. Sheffield LJ and Phillimore HE (2009) Clinical use of pharmacogenomic tests in 2009. The Clinical Biochemist. Reviews 30: 55–65.

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The role of pharmacogenomic testing in psychiatry: Real world examples.

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