Anti-depressants are a finicky class of drugs that often take four tries to ensure a patient receives the right medication, the right dosage, and with few, if any, side effects. Weaning patients off a non-successful drug and then trying another one just lengthens the amount of time a patient has difficulty coping and returning to work. But the growing field of pharmacogenetics is attempting to change all that, with the hope that its successes will include many other drugs down the road.
A number of Canadian life insurance companies are holding pilot programs and trials looking into pharmacogenetics. Through genetic testing, often using a sample of a person’s saliva or a cheek swab, the Centre for Addiction and Mental Health (CMHA) and Assurex Health, for example, are trying to identify genetic variants that can influence how a person responds to various psychiatric medications and side effects.
Some medications, such as the common anti-pain drug, codeine, are inactive until they come in contact with a specific gene that makes it become active, providing the needed pain relief, explains Allison Hazell, clinical director of genetics with Medcan, a Toronto-based company that offers comprehensive individual health assessments. But Hazell says that particular gene may not function very well in some people – or can be in overdrive with others.
Those who choose pharmacogenetics are often on a number of medications and the lab Medcan uses will account for gene-drug interactions as well as drug-to-drug interactions, says Hazell. This way they can find out right away which medications are right for them and which aren’t.
While many companies are currently testing out pharmacogenetics with patients, Hazell says one of the current missing pieces is the cost effectiveness of doing the testing, and in the case of anti-depressants, how long it takes for people to get back to work.
And while companies are currently looking at how to provide patients with the most beneficial anti-depressant drugs, the future could open the door to pharmacogenetics testing with many drugs.
“The vision is five to 10 years from now that when you are at your doctor’s office and they are typing in a requisition for a medication and that’s not a good option for you, a message would pop up saying this medication is not for this person,” says Hazell. “It’s similar to how a doctor will look at your weight or other medications that you are on because they know that all those things can affect your metabolism. It’s an extra piece of information, or a tool, to help take away some of the trial and error that currently goes into choices of medication and doses.”
Medcan is already looking at drugs that deal with cardiovascular and oncology drugs on a pharmacogenetics basis. Hazell says it will still take a while before pharmacogenetics testing becomes part of the mainstream health system, but “it will be standard of care.”