Canada needs drug tracking system
Better information is needed about uses, efficacy and side effects, Jenna Wong and Robyn Tamblyn say.
If you take prescription medications, what conditions do you take them for? Are they working? Have you experienced any negative side-effects?
Answers to these critical health questions aren’t well documented for most Canadians. Yet the answers would provide the crucial information needed to ensure our medications are safe and worth taking.
Before prescription drugs are approved in Canada, they are tested under controlled conditions on relatively small numbers of patients with selective characteristics (patients of certain ages, races, ethnic groups or genders). But once medications are approved, they aren’t monitored as closely as they should be.
We need to significantly improve our system of postmarket surveillance for prescription drugs in Canada to make sure we are continually monitoring their safety and effectiveness in real-world settings. Why? First, adverse drug reactions may surface that were not previously detected in smaller pre-regulatory trials.
Second, the use of a drug may broaden over time to include milder forms of the disease or even different medical conditions that were not assessed during the drug’s pre-market trials. Take antidepressants, for example. These medications are being increasingly used for conditions other than depression.
New research has found nearly one in three antidepressant prescriptions are written for unapproved (“offlabel”) conditions — most of which are not backed by sufficient evidence.
To adequately monitor the safety and effectiveness of medications in real-world settings, we need a timely post-market drug surveillance system that can identify the reasons patients are taking their medications and follow patients to detect adverse drug reactions and determine whether their medications are working.
How are we doing? Not great.
The medical reasons for prescriptions are not often explicitly documented in patient charts, nor is this information required for patients to fill prescriptions or receive reimbursement for drugs. So, when it comes to drugs like antidepressants that can be prescribed for different medical conditions, not knowing why a patient is taking a drug creates major challenges for assessing its effectiveness and appropriateness of use.
Canada’s Adverse Drug Reaction Reporting System has many flaws, including the fact that it relies upon voluntary reporting by physicians via a time-consuming process. It’s estimated that less than five per cent of all adverse reactions are reported to Health Canada.
Once drugs are released onto the market, their realworld effectiveness is not systematically monitored. So, what’s the solution? We need a national postmarket drug surveillance system that mandates the systematic collection of data on the reasons for drug use, adverse drug reactions and effectiveness, and governs the use of health information technologies to collect these data.
When prescriptions are cancelled, renewed or modified, electronic medical record systems could prompt physicians to record details about adverse drug reactions and effectiveness.
Many Canadian provinces have implemented centralized information systems to track all medications patients are receiving. If these systems are to contribute toward an effective post-market drug surveillance system, they need to additionally collect information on the reasons medications are being prescribed and the outcomes they produce.
Jenna Wong recently received her PhD from the Department of Epidemiology, Biostatistics and Occupational Health at McGill University and will begin a research fellowship at Harvard Medical School in 2018. Robyn Tamblyn is an expert adviser with EvidenceNetwork. ca and James McGill professor in the departments of Medicine and Epidemiology, Biostatistics, and Occupational Health at McGill University.