When it comes to personalized prescribing, it’s easy to pick out some of the more urgent and obvious prompts for pharmacogenomic (PGx) testing – new treatment for depression/anxiety, medication, to prevent or treat worsening cardiovascular disease, or planning for pain management after a scheduled surgery.
Ordering a PGx test that may take a week or two to process can still be invaluable as a part of prescribing for all of these but, for many conditions, it’s best not to wait. Sometimes, life happens and you need answers right away.
Infectious diseases often come on seemingly out of nowhere and treatment can be difficult. On top of that, some of the most commonly prescribed medications can have a long list of possible side effects, so effective treatment is going to depend on getting the right medication, right away. And PGx testing can be invaluable for your prescriber.
Just a few of the more common applications for PGx in prescribing for infectious disease include:
Voriconazole is an anti-fungal medication that relies on the CYP2C19 gene to be effective. It’s used to treat infections in the lungs, the esophagus, and the blood. It’s also used to treat certain other fungal infections when other treatments have failed, but up to 50% of the population might not have the right genetic profile for it to be effective. Nearly half of us are either poor or rapid/ultrarapid metabolizers at CYP2C19, both of which should be strongly considered when looking at prescribing voriconazole.
While voriconazole can be life-saving, it also has a list of potential side effects that make the case for PGx testing on their own. Accurate testing can be invaluable in helping avoid side effects, including fever, chills, rapid heartbeat, difficulty breathing, extreme fatigue, and more. What’s more, if you’re one of those that’s a poor metabolizer at CYP2C19 (up to 20% of us), a standard dose could actually lead to an overdose for you. This could show up as: sensitivity to light, drooling, loss of balance, depression, shortness of breath, seizures and extreme fatigue.
Efavirenz is used, in conjunction with other medications, to treat human immunodeficiency virus (HIV) infection. While there have been great advances in HIV prevention and therapy since it was first identified, there are still over one million people in the U.S. living with HIV and there are about 35,000 new cases each year. Effective treatment, with the right medications, are critical to survival and to limiting the spread of the disease.
While efavirenz does not cure HIV, it decreases the amount of HIV in the blood, which may decrease the chance of developing acquired immune deficiency syndrome (AIDS) and HIV-related illnesses like serious infections, or even cancer. By decreasing the viral load in the blood, it could also decrease the risk of transmitting the virus to others.
Efavirenz relies on the CYP2B6 gene for effectiveness and may conflict with a long list of medications, including anti-depressants, statins and blood thinners like warfarin. The only way for a prescriber to navigate accurate prescribing for someone taking multiple medications like these is a robust PGx panel that provides insight into a wide variety of options.
Aminoglycosides are a class of potent, broad spectrum antibiotics that rely on the MT-RNR1 gene and treat a wide variety of serious infections, including endocarditis (an inflammation of the inner layer of the heart), pneumonia, severe urinary tract infections, sepsis and complicated intraabdominal infections. This class of antibiotics has been essential to antibacterial chemotherapy since it was first introduced for clinical use in 1944.
Abacavir, like efavirenz, is used to treat human immunodeficiency virus (HIV) infection but relies on a different gene – HLA-B. One of the primary benefits of a robust PGx panel is to evaluate options for different medications, using different genetic pathways, to see which of the available options is best for that particular individual. If a patient is a poor metabolizer for CYP2C19 (making efavirenz a poor choice) the prescriber can compare against their results for HLA-B to see if that’s a better option.
While it is in a different class of drugs from efavirenz, the goal of decreasing the amount of HIV in the blood is still the same. Lowering viral load allows the immune system to function better, lowers the chances of HIV-related complications and improves the quality of life.
Prescribing for just about any illness or condition can be difficult, given all the potential variables and barriers to effectiveness. Having current results from a proactive PGx test in your medical records could well be one of the most valuable things you could do to give your healthcare providers the information they need to treat you as well as possible, and make your medication therapy just right, just for you.
Learn more about individual PGx testing at www.exactmeds.com
