Currently, pharmacogenetic testing prior to drug use is largely limited to specialised drugs such as chemotherapeutics, where selecting the optimal drug for treatment can have a major impact on both cost and prognosis, making the inconvenience and expense of testing worthwhile.
Although pharmacogenetic testing could theoretically be used for the more common drugs, such as antidepressants, the benefits are less obvious. However, an increasing understanding of the multiple genetic influences on drug action, combined with new technologies that may reduce testing costs, could make it a possibility, especially if a patient could be assessed for their pharmacogenetic profile as part of routine medical assessment and the information stored for future use. This sort of ‘personalised medicine’ is a long way in the future, but potential forerunners of broader pharmacogenetic tests are already emerging.
Pharmacogenetics can only enhance, and never replace the need for proper clinical management, since clinicians and pharmacists must also consider the wide range of non-genetic influences on drug function when selecting the ideal medication for a given patient and condition. Even in situations where the use of pharmacogenetic testing may prevent serious adverse reactions, the clinical utility of such testing is presently contended, with some clinicians arguing that suitably careful scrutiny of patients should allow the rapid identification of adverse drug effects and switching to an alternative.
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