Opioid use disorder and treatment

Learn about opioid use disorder (OUD), risks of opioid use and treatment options. This page focuses primarily on medication-assisted treatment, also known as opioid agonist therapy.

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Opioid use disorder

Opioid use disorder (OUD) is also referred to as opioid addiction. It's a treatable medical condition that changes your brain and body in ways that make it hard to stop using opioids. This is because your body gets used to a regular supply of the drug.

With OUD, you crave the opioid and continue using it despite its harmful effects on you and others. The opioid dominates your feelings, thoughts and activities. However, not everyone who uses opioids will develop OUD.

Risks of opioid use

A physical dependence on opioids isn't the same as OUD. For example, if you've been using opioids for a week or 2 to manage pain, you may become physically dependant on the opioid. However, you are not using the opioid in a way that harms you or others.

You might also experience withdrawal symptoms if you abruptly stop using an opioid. This is your body's natural reaction. It isn't safe or effective to abruptly stop using opioids (sometimes called detoxification or "detox") without medical support.

When your body's opioid supply is cut off too quickly, you can go into withdrawal and become physically ill, anxious and depressed. You may have powerful cravings and experience other severe, painful withdrawal symptoms. This often drives people to start using the opioid again, just to relieve their symptoms.

When you stop using an opioid, your tolerance to it is lowered. If you start again, you're at a higher risk of overdose and death because your body can no longer handle the same amount or strength as before.

If you're considering reducing or stopping the use of opioids (prescribed or not), a health care provider can help you do so safely and effectively. You may need to come off opioids slowly if you've been:

Depending on your personal situation and your usage, this process can take from weeks to months.

Treatment for opioid use disorder

There are different treatment options available, but no standard approach that works for everyone. What works for you may not work for others. You can reduce or stop opioids with effective treatment and follow-up.

The best OUD treatment includes:

If you're struggling with opioid use, talk to a health care provider about your treatment options.

You may need a team to support you, including:

You may also benefit from health and social support, such as:

Opioid agonist therapy (medication-assisted treatment)

Opioid agonist therapy, sometimes called OAT or medication-assisted treatment, is a medical treatment for people with OUD. It reduces your cravings for opioids and prevents severe withdrawal symptoms.

With opioid agonist therapy, long-acting opioid medications are given under the supervision of a health care provider. These drugs act more slowly in the body for a longer period of time. This helps you:

With the correct dose, these medications won't get you high, sedate you or cause trouble with your thinking. You should be able to function, feel and think normally. Opioid agonist therapy has also been shown to:

It can also:

All medication-assisted treatment options work best when combined with other treatment options and services such as:

Before you begin opioid agonist therapy, a health care provider will talk to you about:

Opioid agonist therapy options

There are various options available, including buprenorphine, methadone, slow-release oral morphine and injectable opioid agonist treatment.


Buprenorphine is an opioid medication for treating OUD. When taken at the right dose for you, it will prevent withdrawal symptoms. It will also reduce your opioid cravings without causing you to feel high or sleepy.

When compared to other options, buprenorphine has:

Buprenorphine comes in various forms:

The length of time a person stays on buprenorphine varies. Some people choose to stay on it for years, as it's an effective treatment option.

People are most successful coming off the medication once they've maintained a period of stability. After this is achieved, their dose is lowered very slowly over time.

Methadone (Methadose®and its generic forms)

Methadone is an opioid medication for treating OUD. When taken at the right dose for you, it helps you stop or reduce your opioid use by reducing withdrawal symptoms. It will also reduce your opioid cravings without causing you to feel high or sleepy.

It's a liquid that's taken daily and is often mixed with a fruit-flavoured drink. Someone will usually watch you drink the medication, especially when you start treatment.


Methadone requires more observations and time to get the right dose. The dose must be increased gradually to avoid overdose. It may take a few weeks to find the right dose and schedule for you.

A health care provider supervises the daily doses in a medical setting like a treatment centre, hospital, doctor's office or pharmacy. You may be able to transition to take-home doses once you've been on a stable dose for long enough.

Some people choose to stay on methadone for years, as it's an effective treatment option.

In some cases, it may be possible to eventually stop using methadone. The dose should be lowered very slowly over time to ease the process of withdrawal.

Methadone has strict prescribing practices, which vary by province and territory.

When combined with other social supports, buprenorphine and methadone are effective treatments for opioid use disorder. However, one may work better than the other for some people.

Slow-Release Oral Morphine (SROM) (Kadian®)

Slow-release oral morphine is a daily capsule usually taken at a pharmacy under the supervision of pharmacy staff.

It may be offered to you if you:

Staff sometimes have specific instructions to open the capsule and sprinkle contents into a medicine cup or onto a soft food like applesauce or jam. Sometimes the pharmacist opens the capsule and gives you the pellets to swallow with water.

Injectable Opioid Agonist Treatment

Injectable opioid agonist treatment (iOAT) medication options include:

It can be offered to you if you:

Injectable OAT:

Once you're stable, you'll probably be encouraged to switch from this higher intensity treatment option to another option like:

This reduces the frequency of doses and the risk from ongoing injections.

Availability of injectable opioid agonist treatment varies by province and territory.

Talking to your health care provider

It's important to talk with a health care provider when reducing or stopping opioid use, so you can do so safely and effectively.

You might want to ask your health care provider:

For more information, refer to the:

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