Pharmacogenetics (PGx)

Right Drug, Right Dose Through Personalized Medicine

Doctor’s generally prescribe medications based upon symptoms or because of the results of a physical. However, according to FDA.gov more than 75% of people have genetic variations that affect how they respond to the most commonly prescribed medications.

 

Now, with a DNA assessment called Pharmacogenomics, your doctor can reduce trial and error, and prescribe the most effective medicine and dosage with the least amount of risk and unwanted side effects right from the start.

 

Pharmacogenomics is a science that combines pharmacology, (the science of drugs) and genomics, (the study of genes and their functions). This can determine how our genetic variations affect our individual response to a medication through gene to drug, and drug to drug reactions.   

 

For example, on an individualized basis, pharmacogenomic tests can identify the most effective blood-thinner or anti-depressant and their dosages, or if you will in fact metabolize codeine to morphine, which must happen for it to be an effective pain reliever.

 

Additionally, the results may not only call for a change in your current medications, but they will also be part of your medical records and could be a “road map” for your future medications.

 

If you are being prescribed stimulants, antidepressants, antipsychotics, mood stabilizers, or antianxiety medications:

The personalized results of a your pharmacogenomic test can provide additional information to assist your physician in determining the most effective medication, dosage, and medical protocols specifically for you.

CYP2D6


Genotyping for CYP2D6 and CYP2C19 variations are potentially useful clinical tool to help mental health professionals prescribe psychiatric medications for their patients. CYP2D6 is involved in the metabolism of more than 70 drugs, including many antidepressants and antipsychotics. Based on the CYP2D6 DNA testing for antidepressants, a patient’s doses can be adjusted to minimize drug toxicity.




CYP2C19


Is involved in the metabolism of a wide range of anti-depressants and benzodiazepines. Cytochrome P450 testing can assist in the determination of an individual's required dosage of identified drugs that are metabolized by CYP2D6 and CYP2C19.




CYP1A2


Is primarily responsible for clozapine metabolism. The genetic studies of clozapine drug response are supported by the identification of multiple functional variants in CYP1A2, with well-defined effects on clozapine metabolism. CYP1A2 genetic lab testing can assist in determining the correct doses of this medication.




CYP3A4


Plays an important role also in psycho- pharmacotherapy as it contributes to the biotransformation of various antidepressants, antipsychotics, benzodiazepines.




DRD2/ANKK1


The D2 dopamine receptor encoded from DRD2 is the primary target of most antipsychotic medications. The ankyrin repeat and kinase domain containing 1 gene (ANKK1) is located 10 kb from DRD2 and has been associated with tardive dyskinesia (TD). DRD2 genetic testing can assist in determining dosing for these medications.




CYP2B6


Responsible for the metabolism of the most active metabolite of bupropion




CYP2D6


Shown to have a significant effect on the body’s ability to metabolize atomoxetine




COMT


An enzyme that degrades dopamine and norepinephrine, primarily in the prefrontal cortex of the brain a pharmacodynamic gene which has been implicated in the therapeutic response of patients taking stimulant medications (amphetamines) and some antipsychotics.





A patient’s genetic profile can help define the appropriateness and dosage of many prescribed psychotropic drugs including:

Therapeutic Class                                                   Name of Drug

Antipsychotics

Aripiprazole (Abilify®)
Haloperidol (Haldol®)
Olanzapine (Zalasta®)
Quetiapine
Risperidone (Risperdal®)
Zuclopenthixol (Clopixol®)
Thioridazine (Mellaril®)

Anticonvulsants

Clozaban (Onfi®)
Phenytoin (Dilantin®)

Antidementia                                                           Donepezil (Aricept®)

Selective Serotonin
Reuptake Inhibitors

(SSRIs)

 

Citalopram (Celexa®)
Fluvoxamine (Luvox®)
Escitalopram (Lexapro®)
Fluoxetine (Prozac®)
Paroxetine (Paxil®)
Venlafaxine (Effexor®)

Anti-ADHD

Atomoxetine (Strattera®)

Antidepressants

Amitriptyline (Elavil®)
Clomipramine (Anafranil®)
Desipramine (Norpramin®)
Doxepin (Deptran®)
Imipramine (Tofranil®)
Protriptyline (Vivactil®)
Trimipramine (Surmontil®)

Smoking Cessation Agents

Bupropion (Wellbutrin®)

 

If you are being prescribed Cardiovascular medications:

 

Coronary artery disease medications are influenced by multiple genes that interact in complicated ways. The personalized results of  your pharmacogenomic test can provide additional information to assist your physician in determining the most effective medication and dosage and medical protocols specifically for you.

CYP2D6


Beta Blocker metabolism (carvedilol, metoprolol, yohimbine, timolol); antiarrhythmics (flecainide, mexiletine, propafenone). It metabolizes 25% of all prescribed drugs.




CYP2C9


Is the most abundantly expressed enzyme in the human liver, accounting for the metabolism of approximately 15-20% of prescribed medications such as the anticoagulant Warfarin, the antihypertensive drug losartan, the diuretic Torsemide, and nonsteroidal anti-inflammatory drugs, (NSAIDs), such as ibuprofen, Diclofenac, Piroxicam, Tenoxicam.




VKORC1


VKORC1 gene testing is done for those currently taking or going to take blood thinners and this gene has been connected to Warfarin response. VKORC1 genetic lab testing will help physicians understand potential adverse reactions and appropriate doses.




Factor V Leiden


Inherited Thrombophilia. Factor V Leiden mutation is the greatest common inherited predisposition for hypercoagulability. People with Factor V Leiden mutation with thrombophilia have higher than average risk of developing a deep venosus thrombosis (DVT).




Factor 2 / Factor II


Prothrombin deficiency, thus creating the potential of a hypercoagulable state, a condition that causes your blood to clot more easily than normal.




MTHFR


A decrease in the function or amount of MTHFR causes increased blood levels of homocysteine. Increased homocysteine blood concentrations are associated with an increased risk for cardiovascular disease including venous thrombosis, atherosclerosis, stroke, and peripheral artery disease and thromboembolic diseases and heart attacks. Additionally, an MTHFR variant can cause depression, anxiety, bipolar disorder, schizophrenia, chronic pain and fatigue, migraines, and recurrent miscarriages in women of child-bearing age.




SLCO1B1


SLCO1B1 variants are associated with simvastatin-induced myopathies.




APOE


People who carry APOE have an increased chance of developing atherosclerosis, and to greatly increase the risk of a rare condition such as hyperlipoproteinemia type III. Hyperlipoproteinemia type III is characterized by increased blood levels of cholesterol, certain fats called triglycerides, and molecules called beta-very low-density lipoproteins (beta-VLDLs), which carry cholesterol and lipoproteins in the bloodstream.




CYP2C8


CYP2C8 gene testing can also be done to determine impaired drug metabolism causing adverse drug reactions or lack of therapeutic response to drugs such as ibuprofen. CYP2C8 genetic lab testing will help determine strategy and treatment dose for these medications.





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