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Does Mounjaro lead to stomach paralysis? What risks are associated with Xarelto blood thinner? Does Dupixent cause cancer?
In recent years, Canadians have become increasingly concerned
about the potential side effects of medications — from
everyday prescriptions to vaccines to newer biologics like Entyvio
(vedolizumab) and Dupixent (dupilumab).
Understanding how to find credible, science-based answers to these
questions is crucial. This guide explains how Canadians can locate
and interpret official safety warnings for prescription and
over-the-counter drugs, including emerging concerns about
pharmaceuticals.
Where can I find copies of side effect warnings for drug products?
The most reliable and detailed source of side effect information is each product's Product Monograph1 — a factual, science-based document required by Health Canada during the approval process. It includes information about all known and potential risks, ranging from minor side effects (like headaches or mild rashes) to serious ones, such as possible malignancies or immune disorders.
Copies of product monographs (and accompanying side effects warnings) for drugs marketed in Canada are publicly accessible online through Health Canada's Drug Product Database2. The Drug Product Database has information on every approved drug — past and present — and provides downloadable copies of each Product Monograph.
You can search by:
- Brand name (e.g., Suboxone, Mounjaro, Dupixent)
- Active ingredient (e.g., buprenorphine, tirzepatide, dupilumab)
- Manufacturer name
Each entry lists the Drug Identification Number (DIN), regulatory history, and the latest monograph version.
If a Product Monograph is unavailable or you wish to cross-check international data, an alternative place to look for relevant drug product documents is the U.S. Food and Drug Administration's Drugs@FDA database. Because Health Canada and the FDA sometimes differ in labelling standards, you may want to consult both if you are looking for a complete picture.
What information on side effects are drug companies required to disclose?
Under Canadian law, drug manufacturers must warn consumers of any dangers they know — or reasonably should know — about their products. Because medications directly affect the body, pharmaceutical companies are held to a particularly high standard.3
Health Canada and other regulators require manufacturers to disclose adverse reaction events in Product Monograph so that patients and doctors can monitor for warning signs. However, not all potential side effects are always prominently highlighted in a Product Monograph.
If you are concerned whether a side effect has been linked to a certain drug, it helps to learn how to read and review a Monograph to find all the relevant information you may be looking for.
How should I properly read and understand the side effect warnings for a drug?
A Product Monograph is divided into three parts:
- Part I: Health Professional Information – detailed data for doctors and pharmacists
- Part II: Scientific Information – summaries of clinical trials and laboratory studies
- Part III: Patient Medication Information – a plain-language summary designed for consumers
If you're looking for key warnings, start with the Patient Medication Information section.
Serious hazards are usually listed in a boxed section titled "Serious Warnings and Precautions."
Further down, the section "What are possible side effects from using [Drug Name]?" summarizes both serious and minor adverse effects, along with instructions on when to seek medical help.
For deeper detail, turn to the "Warnings and Precautions" or "Adverse Reactions" sections in Part I of the monograph. For example, in Dupixent's case, the "Adverse Reactions" section includes reports of malignancies such as CTCL and other lymphomas. Wording in the adverse reactions section signals that such events were observed in patients even if the manufacturer may dispute whether a causal relationship is established.
How can I know when changes to side effect warnings happen?
Even after approval, new side effects can emerge as more people use a drug. For example, the possible connection between Dupixent and cutaneous T-cell lymphoma appears to have received more coverage in scientific literature after years of post-marketing surveillance, after more dermatologists began reporting cases of persistent skin lesions that later tested positive for CTCL.
To track whether new risks have been added to your medication, check the "Recent Major Label Changes" section at the start of the Product Monograph.
Health Canada requires that any major safety or efficacy updates made in the past 24 months be summarized there. Within the document, new or revised text is marked with a vertical line along the left margin.
What are the key things to remember when it comes to researching drug side effects?
Whether your concern is Suboxone and dental problems, Dupixent and CTCL, or Xarelto and bleeding risks, reliable safety information is available — but it requires knowing where and how to look.
Always start with the Health Canada Drug Product Database, review the Product Monograph, and monitor for updates. When questions arise about complex or serious risks like cancer, consult your healthcare provider and request a review of the latest official safety data.
In an age where health misinformation spreads easily online, understanding how to find official drug warnings is crucial. Like all modern therapies, pharmaceuticals like Dupixent can offer life-changing benefits to many patients — but ongoing awareness and informed vigilance ensure that those benefits are balanced with safety.
Footnotes
1. https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/applications-submissions/guidance-documents/product-monograph/frequently-asked-questions-product-monographs-posted-health-canada-website.html
2. https://health-products.canada.ca/dpd-bdpp/
3. Hollis v. Dow Corning Corp., 1995 CanLII 55 (SCC), [1995] 4 SCR 634
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
