The human genome includes 3 billion nucleotide base pairs in the DNA that constitutes our 25,000 to 30,000 genes. The genes are responsible for coding of functional and structural proteins. A number are pharmacogenomics proteins—drug receptors, drug targets, drug metabolizing enzymes and drug transporters—important to accurate and effective medication therapy. These include, but aren’t limited to, the Cytochrome P450 enzymes—CYP2D6, CYP2C9, CYP2C19, CYP3A4/5, and others. Other proteins, such as VKORC1 and SLCO1B1 represent drug targets and transporters, respectively. These example proteins among others are critical in the application of pharmacogenomics in precision medicine.
Variances in the activity of these enzymes may affect an individual’s pharmacokinetics (absorption, distribution, metabolism and excretion) as well as the pharmacodynamics (what effect the medication has on the body) of each medication the individual is taking.
In the metabolism of drugs, an individual can be classified in one of five categories (metabolism phenotype) based on the activity of these pharmacogenomic proteins as defined by the Clinical Pharmacogenetics Implementation Consortium (CPIC):
- Normal (formerly extensive metabolizer) (NM/EM)
- Fully functional enzyme activity.
- Intermediate metabolizer (IM)
- Decreased enzyme activity (activity between normal and poor metabolizer).
- Poor Metabolizer (PM)
- Little to no enzyme activity.
- Rapid Metabolizer (RM)
- Increased enzyme activity compared to normal metabolizers but less than ultra-rapid metabolizers.
- Ultrarapid Metabolizer (UM)
- Increased enzyme activity compared to rapid metabolizers.
By considering an individual’s genetics relative to drug metabolizing enzymes, targets, receptors and transporters, healthcare providers can now more precisely help patients to reach optimal drug therapy.
Examples of drug-gene interactions for which pharmacogenomics can help optimize therapy:
- Codeine – CYP2D6
- Warfarin – CYP2C9
- Clopidogrel – CYP2C19
- Carbamazepine – HLA-B*15:02
Integrating Into Your Practice
The truth is that not every medication is safe and effective for everyone. For the first time, PGx allows healthcare providers to look inside a patient – at their DNA – to gain insight as to how they will process and respond to medications, taking the much of the guesswork out of prescribing medications and improving patient outcomes.
Through partnerships with Manchester University and PGx testing providers, RxGenomix is providing everything healthcare providers need to integrate pharmacogenomics into their practice. RxGenomix is working closely with Manchester University to provide extensive education on the science while our testing partners are a sole-source provider of testing support.
Our team works directly with pharmacists and other healthcare providers to help them:
- Identify candidates for pharmacogenomic testing
- Collect and process the buccal swab sample
- Retrieve the results
- Collaborate with the prescribing physician on potential medication changes
To learn more about this process OR to enroll in the RxGenomix Training Program in Pharmacogenomics, contact us.