About opioids
Opioids are psychoactive substances, either naturally occurring or synthetic, that act on the brain by changing the perception of pain, generally to relieve it. Misuse can lead to serious health risks.
Many people turn to opioids for their analgesic properties. Opioids have beneficial effects when used as prescribed by a doctor and under the guidance of a healthcare professional. They can help relieve pain caused by various temporary or chronic health issues. How they are taken can vary depending on the medical or non-medical context.
Here are a few examples of opioids sold with a medical prescription:
- Oxycodone
- Morphine
- Hydromorphone
- Fentanyl
- Codeine
- Methadone
Opioids can be prescribed in different forms, including syrups, tablets or capsules, nasal sprays, transdermal patches, suppositories or liquids for injection.
Methods of consumption
The method of opioid use may be:
- oral (tablets, capsules, liquids)
- transdermal (patch)
- by injection (intravenous, intramuscular or subcutaneous)
- sublingual or buccal (lozenges)
- by inhalation or smoking
- intranasal (by snorting)
Risks relating to prescribed opioids
Opioids, even when prescribed by a physician, can have health risks if they are used inappropriately. Among these risks, we can mention dependence (addiction) and overdose.
Some people may be tempted to use medications that have been prescribed for someone else. This carries several serious health risks, even if the symptoms may seem similar:
- effect of inappropriate dosage
- allergies and intolerances
- unexpected side effects
- possible interaction with another prescription medication
Limit the risks associated with prescription opioids
You can limit the risks related to using prescribed opioids by taking the following precautions:
- Avoid mixing opioids with other depressants such as alcohol and benzodiazepines
- Always follow the dosage and recommendations of your doctor. If you are no longer able to follow these recommendations, talk to a health professional about it. If you are unsure, you can also talk about it anonymously and confidentially by contacting Drugs: Help and Referral
- Throughout Québec: 1-800-265-2626
- In the Montreal region: 514-527-2626
- Keep opioid medications in their original packaging to know what they are and the consumption guidelines
- Store opioids in a secure location, out of reach of children and adolescents
- Return any expired or unused opioid medications to the pharmacy to avoid improper use. To avoid harming the environment and human health, never throw medication down the toilet or sink
Risks relating to black market opioids
Some people may buy opioids on the unregulated or “black” market. This carries significant risks. Indeed, some opioids sold illegally, such as fentanyl, heroin or counterfeit Xanax, Ritalin or Valium tablets come from clandestine laboratories that do not ensure the quality of the product.
The high toxicity of illicit substances leads to high risks of overdose associated with black market opioids because the exact composition of these substances is unknown. A person is therefore at risk of experiencing an accidental overdose, even without abusing the substance or irrespective of whether or not they use it regularly. An overdose occurs when the body can no longer tolerate the use of a toxic substance.
Limit the risks associated with black market opioids
Precautions can be taken to reduce the risk of overdose when using opioids or other kinds of proactive substances procured on the black market:
- Keep on hand naloxone at all times:
- Know how to recognize the signs and symptoms of an opioid overdose and be sure that you always keep a naloxone kit on hand
- Depending on the situation, more than one dose of naloxone may be needed. To get this opioid overdose antidote and learn how to use it, see the page Find a resource that can provide naloxone
Services during festivals or events
If you are using drugs at a festival, ask the organizers if there is a harm reduction organization on site. Workers will answer your questions and give you naloxone kits or safe drug use equipment and possibly test strips for substances such as fentanyl. Make sure you find out where the organization or a medical services tent is and, in the event of an overdose, don’t hesitate to ask for help.
- Know the drugs you are taking and the effects they can have on you:
- Learn about the drugs, the ways they are used and the effects they may have on you
- Consider how long these effects could last. To find out more, check out the page Recognizing drugs and their effects
- Some drugs may be mixed with opioids. When using drugs, such as amphetamines, cocaine or MDMA (ecstasy), it is important to recognize unusual effects that could occur even if you are not using opioids
- Find out about the Good Samaritan Law:
- The Good Samaritan Drug Overdose Act provides some legal protection for people who seek emergency help during an overdose
- Seek emergency intervention when you are a witness of an overdose, without fear of being charged with possession of a controlled substance
- Avoid using drugs when you are alone:
- Use in the presence of others and, ideally, not all of you at the same time, or make sure there is someone who does not use who is able to intervene in the event of an overdose
- Before using, let your loved ones or a worker know
- Tell a friend, loved one or neighbour if you feel drowsy or tired or are having a hard time speaking or dealing with the effects of the drug. Avoid isolating yourself
- Whenever possible, use in a supervised consumption site
- Keep a record of the substance you use and the time of day. In the event of an overdose or other problems, this information could enable rescue workers to act more quickly and effectively
- Start off with small doses:
- Take a small amount of the drug and wait awhile before taking more
- Watch for any unusual reactions and, when in doubt, stop taking the drug
- Assess future doses based on the drug and its effects
- Have your drug tested:
- Drugs available on the black market may contain unexpected, highly potent and potentially lethal substances. Having the composition of your drug checked before taking it can reduce risks. Resources offering these services are available in several regions of Québec
- Avoid using multiple substances:
- Don’t underestimate the effects of mixing psychoactive substances (for example, alcohol and other drugs). Harmful or unpleasant effects may increase if you combine two or more substances
- Opioid use is especially risky if they are taken with other depressants such as alcohol, GHB or benzodiazepines. If you choose to use these substances, reduce your doses and wait until you feel the effects before using again
Opioid overdose
Signs and symptoms
A person might be experiencing an opioid overdose if, after knowingly or unknowingly consuming the substance, they show the following signs and symptoms:
- They do not react to sound
- They do not react to pain when you pinch them, for example, or when you stroke their skin at the sternum
- They have laboured or snore-like breathing, or they are not breathing
However, there may be other signs and symptoms that do not look like these.
If in doubt, administer naloxone.
If a person is experiencing an overdose, you must take action quickly, call emergency services and administer naloxone.
Rescuing a person who is overdosing on opioids
An overdose is a medical emergency. If you suspect that someone is overdosing, you must act quickly. For information on how to proceed, see the page Rescuing a person from a possible opioid overdose.
Opioid dependence (addiction)
The more a person uses opioids, the more likely they are to become dependent on these substances. Regular use causes a person to develop a tolerance, and they may want to use often and increase their doses to feel the same effects as the first time. Long-term use can cause physical and psychological dependence.
Dependence treatment and opioid use disorder (OUD)
Treatment for opioid dependence usually includes a combination of pharmacological treatment with opioid antagonists (OAT) (such as buprenorphine or methadone) and psychosocial support.
Treatment of opioid dependence:
- Prevents the onset of withdrawal symptoms
- Decreases the persistent need to use
- Reduces the effect of opioids, without producing euphoria
Finding a resource
For more information on opioids and for resources that provide access to treatment for opioid dependence, contact:
Last update: January 23, 2026