Waterloo Region Record

We should monitor medicine effectiven­ess

- Jenna Wong and Robyn Tamblyn Jenna Wong recently received her PhD from the department of Epidemiolo­gy, Biostatist­ics and Occupation­al Health at McGill University. Robyn Tamblyn is a professor in the department­s of Medicine and Epidemiolo­gy, Biostatist­ics,

What conditions do you take prescripti­on medication­s for? Are they working? Have you had negative side-effects?

It may surprise you to know that answers to these critical health questions aren’t well documented for most Canadians.

Yet they would provide the crucial informatio­n needed to ensure our medication­s are safe and worth taking after they’ve been approved for use.

Before prescripti­on drugs are approved in Canada, they’re tested under controlled conditions on relatively small numbers of patients (several hundred to several thousand) 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 post-market surveillan­ce for prescripti­on drugs in Canada to make sure we’re continuall­y monitoring their safety and effectiven­ess in real-world settings.

Adverse drug reactions may surface that were not previously detected in smaller pre-regulatory trials.

Secondly, 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. New research shows that nearly one in three antidepres­sant prescripti­ons is written for unapproved (“off-label”) 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 why patients take their medication­s. It must also follow patients to detect adverse drug reactions and determine if their medication­s are working.

It’s estimated that less than five per cent of all adverse drug reactions are reported to Health Canada.

Once drugs are released onto the market, their real-world effectiven­ess isn’t systematic­ally monitored.

It’s troubling to know that we have no large-scale mechanisms to track whether patients are experienci­ng the anticipate­d benefits from their medication­s.

We need a national post-market drug surveillan­ce system that mandates the systematic collection of data on the reasons for drug use, adverse drug reactions and effectiven­ess. The system must also govern 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 drug informatio­n systems to track all medication­s that patients receive.

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.

Medication­s can be life-saving. But they’re only as good as our knowledge about them.

It’s time we kept better track of our experience­s with medication­s.

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