Drug response testing or pharmacogenetic testing entails investigating genetic variations that influence drug response in individuals. Many factors such as gender, age, environmental factors, diet, body mass, the presence of other medications, chemicals such as nicotine in cigarettes, disease and genetic factors play a role in determining how an individual would respond to a particular medication.

Among these factors, genetics has been found to be a major factor.
Pharmacogenetic testing aims to provide useful information about a person’s genetics which can help guide clinicians and pharmacists in selecting medications that may be most effective for treatment.
Preemptive drug response testing is done to provide guidance in predicting an individuals response to a specific drug or broad range of drugs. This means that it can either be a comprehensive pharmacogenetic test in which an individuals response to a broad range of drugs is investigated or a drug-specific pharmacogenetic test in which an individuals response to a specific drug is the subject of investigation.

A comprehensive pharmacogenetic test involves testing to highlight a person’s likely response to a broad range of medications. It can be based on a particular drug class but must involve testing for more than one drug type.
Pharmacogenomic working group guideline is available for many drugs including acenocoumarol, amitriptyline, azathioprine amongst others. On the other hand, when the testing is centred around a single medication such as specific Statin or antidepressant medications, the pharmacogenetic testing is said to be drug-specific.

Different individuals may respond to a particular medication in different ways. Some individuals may be very responsive to a particular medication; some others may be partially responsive or non-responsive while some may even suffer adverse reactions of the drug. The information provided by preemptive drug response testing will benefit patients, clinicians and general health care as it helps clinicians and pharmacists tailor prescriptions to suit specific needs of patients.

Some medications such as statin and antidepressant medications are known to have undesirable side effects in some individuals. In cases where it is required to prescribe these kinds of medications, a preemptive pharmacogenetic test would come in handy. Results from a preemptive pharmacogenetic test for any of these medications can help guide a clinician in prescribing a medication that may have minimal or no side effects in these individuals. In cases where a drug is known to have varying effectiveness, pharmacogenetic testing can help guide your healthcare provider in selecting prescriptions and dosages that are optimum for the patient.

In emergency situations or ER cases where clinicians may be unsure of how a patient would respond to medication if such a patient has done PGx testing for such medications, a faster and better therapy can be set up for the patient.
PGx testing aims to reduce the trial and error method of prescribing in clinical practice, and it works towards a future where prescriptions, medications and medicine, in general, can be tailored to meet an individual’s specific needs.
A PGx test can only be requested through your specialist, GP or professional healthcare provider.


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