Everyone responds to drugs differently, but now a pilot program at UBC hopes to predict an individual patient's negative reactions to a new drug before that patient receives a prescription.
The Genomics for Precision Drug Therapy project will collect saliva samples from 200 people and will decode the DNA.
"My DNA and your DNA is about 99 per cent similar, but it's the differences that really matter when it comes to you or I, when it comes to drugs," principal investigator Corey Nislow told CBC Radio's The Early Edition.
"There are letters in your DNA code that say either you should be avoiding this particular drug or your dose should be higher or lower."
This pilot study focuses on an anti-coagulant drug, Warfarin — a drug for which Nislow said there is already good research to build on.
In the future, the research could expand to other anti-coagulants, anti-psychotic drugs and antidepressants.
Nislow hopes the research will eventually help doctors give patients more accurate prescriptions.
"We want to get away from this trial and error where we start you on a dose based on educated guesses, and then keep adjusting your dose and then keep adjusting your dose until we hit the right dose," he said.
"It's costly, it's unpleasant and that's more time that you're not on the right dose."
To hear the more about the pilot project, click the audio labelled: What genes can tell us about drug effects.