Opioids: What Are They? (fact sheet)

What are opioids?

Opioids—like fentanyl, morphine, oxycodone and hydromorphone—are medications that can help relieve pain.

What is the difference between legal and illegal opioids?

Legal opioids are prescribed by a health care professional, most often to treat pain from conditions such as sports injuries, dental procedures, short-term acute pain or long-term chronic pain.

Illegal opioids are any opioids that are made, shared or sold illegally. Illegal opioids include:

  • street drugs
  • opioids given to you by someone who is not your health care provider
  • opioids that are not prescribed to you but are stolen or taken from someone else

It is illegal to have opioids without a prescription or to share them with someone—even if you give them away.

Prescription opioids exist in many forms, including:

  • tablets
  • capsules
  • syrups
  • solutions
  • nasal sprays
  • skin patches
  • suppositories

Some over-the-counter medications contain low amounts of codeine, which is an opioid. These can be sold without a prescription. These codeine medications can still be used improperly if you do not follow the directions on the package.

How can opioids lead to a substance use disorder (addiction)?

Unlike some other medications (e.g., antibiotics), opioids are psychoactive substances. This means that they affect your mind, mood and mental processes and can also induce euphoria, or the feeling of being “high.” This creates the potential for them to be used improperly.

What is fentanyl?

Fentanyl is a powerful synthetic opioid that is prescribed to treat severe pain.

Canada’s illegal drug supply is increasingly being contaminated with illegal fentanyl. Most of the illegal fentanyl in Canada is produced in other countries and imported into Canada.

Fentanyl is a dangerous drug because it is 20 to 40 times more potent than heroin and 100 times more potent than morphine, which makes the risk of accidental overdose very high. There is no way to know how much fentanyl has been mixed into illegal drugs because you can’t see, smell or taste it. Consuming as little as a few grains of salt worth of fentanyl can kill you.

If you’re prescribed an opioid, you should:

  • Talk to your health care provider
  • Take it as prescribed
  • Never give away opioid medications that are prescribed to you
  • Never take opioids with alcohol
  • Never take opioids with other medications, unless your doctor tells you it’s okay
  • Never keep, throw out or flush unused or expired opioids; take them back to the pharmacy  for proper disposal

Get the facts at Canada.ca/Opioids


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Organization: Health Canada

Type: Fact sheet

Date published: March 2019

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