About adverse reactions (side effects)
An adverse reaction or side effect is a harmful and unintended response to a health product. The reaction occurs at doses normally used or tested to:
- diagnose
- treat or prevent a disease, or
- alter a bodily function, such as:
- growth
- digestion
- circulation
- respiration
- metabolism
A serious adverse reaction is a harmful and unintended response to a health product. It may occur at any dose and:
- requires in-patient hospitalization or extends hospitalization
- causes congenital malformation (birth defect)
- results in persistent or significant disability or incapacity
- is life-threatening or results in death
You may experience an adverse reaction even when using the product as directed. Reactions may become apparent within minutes or years after exposure. These can range from minor reactions, like a skin rash, to something more serious, like a heart attack or liver damage.
Health products that may cause an adverse reaction include:
- prescription and non-prescription medications
- biologics, such as
- biotechnology products
- vaccines
- fractionated blood products, such as
- albumin
- immune globulins
- plasma-derived clotting factors
- human blood and blood components, such as
- plasma
- platelets
- whole blood
- red blood cells
- human cells, tissues and organs
- cannabis products
- natural health products
- radiopharmaceuticals
- disinfectants and sanitizers that claim to disinfect
Why it is important to report an adverse reaction
Reporting an adverse reaction helps us to:
- identify potential safety issues
- undertake regulatory actions, such as removing a product from the Canadian market
- communicate changes in product safety information to industry, hospitals and consumers
- identify previously unrecognized rare or serious adverse reactions
- add to international data on the benefits, risks or effectiveness of drugs and health products
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