Our genes can influence the effectiveness of medicines. Yet patients often receive the same pill, which can lead to side effects or reduced effectiveness, for example. If only there was a test that could help you avoid those problems.
The good news is: a genetic test has been around for a long time. It is used in oncology, among other things to check whether a patient is able to tolerate certain types of chemotherapy. If not, you can choose an alternative that will work better. The test is also used in psychiatry to prescribe antidepressants tailored to the patient and to minimize side effects.
Preventing misery
Very good, says pharmacist Jan-Hein Koops from Apotheek Sappemeer. But the pharmacogenetic test is often not yet available for larger patient groups. “It is time for that to change,” says Koops. “A lot of misery can be prevented if you can estimate how someone will react to it before starting a new medicine.”
The Royal Dutch Society for the Promotion of Pharmacy (KNMP), the professional and trade organization for pharmacists and pharmacies, has drawn up a list of more than 90 types of medicines for which genes influence their effectiveness. One of these is clopidogrel. “If someone has a cerebral infarction, clopidrogel, a blood thinner, is often prescribed,” explains Fadia Hadi, a master’s student in pharmacy in Groningen. “The drug and the dosage are standard, while it is already known that the standard dose of clopidogrel does not provide the desired effectiveness for everyone.”
Unacceptable
Research shows that more than 20 percent of clopidrogel users are not able to properly convert the drug. The cause is genetic. The liver enzymes that make clopidrogel effective are less active, causing the drug to lack the desired effect. “This increases the risk of a second stroke,” says pharmacist Koops. “That is unacceptable, especially considering that the risk can be significantly reduced using a simple test.”
Because you have to start somewhere, Koops has started a project together with Hadi to offer more than 200 clopidrogel users from Apotheek Sappemeer a pharmacogenetic test. The response is great. “It is very accessible,” says Hadi. She shows an envelope containing two large cotton swabs. “Just take a sample of the cheek swab and you’re done.” The material goes to Certe, where it is analyzed. In addition to clinical chemist Jelmer van Zanden from Certe, Hadi and Koops also work on the project with GP Brunt and practice manager Sandra van Oerle from the Hoogezand-Sappemeer Group Practice.
Other medications
“Thanks to the pleasant cooperation, the project is going extremely well. I have not tested everyone yet, but so far it appears that more than 25 percent of our clopidrogel users do not break down the drug properly,” says Hadi. “That is a large group.” Hadi and Koops’ advice to the GP is that the dosage of these patients is adjusted or that they receive a different medicine.
It is also examined what other consequences an abnormal enzyme activity has for the rest of the drug use. “In the future, when the patient comes to the counter with a prescription for a new medicine that is broken down by the same liver enzyme we tested for, a message will automatically be displayed and action will be taken,” says Koops.
“We are currently only focusing on clopidrogel, but you can also investigate the effect of other medicines just as easily,” says Koops. The test costs, around 75 euros, are still covered by the deductible. “It is high time that pharmacogenetics is widely introduced and that the costs of this extra care are covered by health insurers, because it can save lives.”