Limiting the unknowns involved in taking prescription drugs

$17.5 million to fund post-market drug safety and effectiveness research

- November 8, 2011

Dr. Ingrid Sketris, professor in the College of Pharmacy. (Danny Abriel photo)
Dr. Ingrid Sketris, professor in the College of Pharmacy. (Danny Abriel photo)

Picking up a prescription has never been easier than it is today. Within a few minutes of leaving the doctor’s office, a patient can have their antibiotic, oral contraceptive, or asthma inhaler from the local pharmacy and walk away with the medication they need. But how much does that patient really know about the drug they’re about to take? And how much does the physician really know about the drug they’ve just prescribed?

Fortunately, a pan-Canadian group of researchers is working on decreasing the unknowns involved in taking prescription drugs using observational epidemiology – the population based study of epidemic diseases using clinical observation, not experiments. 

On October 31, the Government of Canada announced it would provide $17.5 million to fund post-market drug safety and effectiveness research.

Dr. Ingrid Sketris, a professor in the College of Pharmacy at Dalhousie, is one of 60 researchers across Canada collaborating in various projects over the next five years examining the safety and effectiveness of prescription drugs once they’ve been made available to the public. Dalhousie has been awarded $1.975 million for their part in this project, which is being led by Dr. Adrian Levy in the Faculty of Medicine.

Combining expertise


Before any drug goes on the market, it’s screened in labs and rigorously tested in various populations through clinical trials. When safety and effectiveness has been established, the drug receives regulatory approval by Health Canada and subsequently is available on the Canadian market.

Unfortunately, clinical trials are usually done in a relatively short period of time with a relatively small and specific selection of people. This, according to researchers, can create problems for patients who don’t fit in to a specific category that was studied.

“Clinical trials may exclude, for example, elderly people, pregnant women, or people with more than one illness and taking more than one prescription drug,” explains Dr. Sketris. “All of a sudden, the drugs that didn’t have side effects in the clinical trials are available to all types of people with all types of health issues.”

With over 16,000 prescription drugs on the Canadian market, it’s difficult for clinicians to study large numbers of people over extended periods of time.

“In some instances, we may know about the side effects of drugs for five years after the initial prescription was given,” says Dr. Sketris. “But what about 10 years from now, 15 years from now?”

“If a patient starts taking diabetes medication when they’re 50, who’s to say that medication is still the right drug 15 years later when they’re 65? Maybe their condition has changed or they’ve developed new diseases needing other drug therapy. Part of our job as researchers is to help improve the benefits from drug therapy while decreasing the risks.”

In the next several months, the network of researchers across Canada involved in this study will gather anonymous patient data and examine the safety and effectiveness of various prescription drugs.

By combining expertise from multiple centres across Canada, Dr. Sketris is confident the results will make a significant impact on the safety of prescription drugs.

“Prior to this initiative, with thousands of drugs on the market, each individual centre was only able to take on a limited number of projects per year,” explains Dr. Sketris. “With this new funding, we’ll be able to study more drugs in larger populations over longer periods of time.”

Knowledge translation


Once the information is collected, an equally important component of the research project is the ‘knowledge translation’ where researchers synthesize, interpret and circulate that information to various users: doctors, policy makers, educators, community leaders, patient groups, media outlets, and private sector organizations.

“We provide our findings to Health Canada regulators, for example, who will decide if prescription drugs should have a warning for a specific population,” Dr. Sketris says. “We also provide family doctors with this information so they’re able to say for example, ‘your chances of getting this side effect by taking this drug are one in a thousand’ or ‘When you take this drug, avoid taking this other drug.’”

“We’re giving users more precise information in the most effective way. This project is very exciting and will help place Canada as a leader in post-market observational drug safety studies.”

Safety and effectiveness


The Canadian network for Observational Drug Effect Studies (CNODES) will be led by Dr. Samy Suissa of McGill University. Each provincial arm will be led by experts in public health, clinical care pharmacy, epidemiology, statistics and computer sciences. CNODES is supported by a larger national initiative known as the Drug Safety and Effectiveness Network (DSEN) coordinated by the Canadian Institutes of Health Research.

Three major objectives that will be carried out over the next few years are:

  • capacity building in people with funds to support grad students and highly qualified personnel

  • capacity building in data use with new tools and methods developed to better analyze potential problems like drug-drug interactions

  • results where drug safety and effectiveness from this research are combined with existing information to help  inform doctors and pharmacists and improve care of patients across Canada.  



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