Your DNA might hold crucial information that your physician overlooks when prescribing medications.
A recent study published on Wednesday in Science Translational Medicine revealed that almost 25% of participants had received prescriptions that could have been altered in drug choice or dosage due to their genetic makeup.
Conducted by researchers from the University of Pittsburgh, the study analyzed 16 genes that influence the body’s reaction to various medications.
Researchers evaluated DNA samples from 98,590 individuals enrolled in the National Institutes of Health’s All of Us Research Program, correlating these samples with medical records when accessible.
Each participant possessed at least one significant genetic variation that could influence their response to specific medications, with an average of nine variations per individual. Among those with both genetic and clinical information, 24.4% had been prescribed at least one medication that, according to genetic guidelines, should have been substituted with an alternative or adjusted in dosage.
Nonetheless, the research did not confirm whether patients faced side effects or if their treatments were ineffective due to their genetic characteristics.
Dr. Philip Empey, the study’s senior author and an associate professor at the University of Pittsburgh’s pharmacy school, asserts that understanding a patient’s genetic profile can minimize the trial-and-error process often associated with medication.
“Anything we can do to more accurately predict the best medications and dosages on the first try can help us reduce that trial and error,” he stated.
A pharmacist organizes medications at a pharmacy in Vancouver in October 2022. Genetic differences can impact how patients respond to medications, necessitating adjustments in dosage or alternative prescriptions. (Darryl Dyck/The Canadian Press)
Identifying the right medication
Common medications such as omeprazole and pantoprazole for acid reflux, along with atorvastatin for cholesterol management, were frequently prescribed to participants whose genetic profiles suggested potential treatment modifications.
According to Empey, certain genetic variations may heighten the likelihood of muscle-related issues for patients taking statins like atorvastatin, which are intended to mitigate heart attack or stroke risks.
This insight could enable healthcare providers to select alternative medications or fine-tune treatment plans.
“It empowers clinicians to make informed choices, like considering, ‘Perhaps we shouldn’t use that cholesterol medication. Maybe we should start with a lower dosage. Perhaps we should monitor specific toxicities more closely,'” Empey explained.
For certain drugs, the implications can be more severe.
Experts consulted by CBC News indicate that genetic testing can pinpoint patients unlikely to efficiently respond to clopidogrel (Plavix), a medication prescribed to prevent blood clots post-cardiac stenting, allowing for alternative treatments.
Dr. James Kennedy leads the Tanenbaum Centre for Pharmacogenetics at Toronto’s Centre for Addiction and Mental Health. He notes that while genetic testing can aid in medication selection, other aspects like diet, lifestyle, and existing medications must also be factored in. (CBC)
A guideline, not a guarantee
Dr. James Kennedy remarked that the study’s findings were not unexpected but praised the genetic diversity and representation of individuals of African descent within the research.
Kennedy’s team has conducted genetic testing for around 11,000 patients, many of whom had previously tried two or three antidepressants without satisfactory outcomes.
He mentioned that approximately 8 to 10 percent of individuals metabolize certain commonly prescribed antidepressants at an unusually slow rate, leading to medication accumulation and possibly adverse effects.
Kennedy emphasized that genetic testing is particularly beneficial for patients who have encountered challenges with multiple medications.
However, he cautioned that DNA testing alone cannot predict a patient’s response to a specific medication. Factors such as concurrent medications, smoking habits, and dietary choices must also be considered.
“We say, ‘Here’s your genetic blueprint, here are some tendencies you might have, and now let’s discuss all the other factors to consider before making a final decision,'” he stated.
A 2023 European clinical trial referenced in the study indicated that genetic testing prior to prescribing certain medications decreased the incidence of adverse drug reactions. However, incorporating such testing into routine practice in Canada presents challenges.
A researcher at the University of Calgary holds a diagnostic kit used to detect genetic variations in February 2024. While such testing could assist doctors in customizing medications for individual patients, cost and logistical challenges have limited its widespread implementation in Canada. (Jeff McIntosh/The Canadian Press)
Challenges in Canada for universal testing
Dr. Jacob Udell, a cardiologist based in Toronto, noted that the study was commendable, especially due to the participant genetic diversity, but emphasized that few healthcare providers in Canada or the U.S. routinely test patients for genetic variations to gauge their medication metabolism.
“It’s not typically a priority for frontline clinicians,” he remarked.
Udell explained that for many conditions, a physician can prescribe a drug, observe the patient’s response, and make necessary adjustments, usually without significant consequences. This method can be more feasible than conducting routine genetic screenings.
He also questioned whether implementing widespread testing should take precedence while Canada’s healthcare system is grappling with fundamental service provision challenges.
“We’re currently focused on ensuring everyone has access to a family doctor,” he said.
In addition to the testing costs, Udell pointed out that clinicians would need access to genetic test results, along with the expertise to interpret them.
Empey concurred, stating that making genetic testing standard practice would necessitate substantial investment in training, infrastructure, and new systems for sharing results among healthcare providers.
“The scientific evidence is robust for many medications. The challenge of implementation becomes more about economics, processes, and education,” he concluded.
For the time being, Empey recommends that patients inquire with their doctors or pharmacists regarding the potential benefits of genetic testing and share any relevant outcomes with them.
Udell cautioned that private genetic testing might become more prevalent for those who can afford it, “but that won’t assist those who cannot pay for the testing.”
