Risks of opioids

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Opioids are powerful medications that can have risks of physical dependence, tolerance and addiction even if you take them exactly as prescribed and without any side effects. Learn about these risks and how to work with your health-care team to prevent overdose.

Key points

  • Over long periods of time, daily use of opioids can create a risk of physical dependence, tolerance and addiction.
  • Physical dependence is not the same as addiction. You will usually experience the signs of physical dependence, such as uncomfortable withdrawal symptoms, if you suddenly stop the medication.
  • Your health-care team will work with you to gradually stop the medication and prevent or ease withdrawal symptoms.

Opioids are powerful medications. Even if you take them exactly as prescribed and without any side effects, they have the following risks:

If someone fails to follow the instructions on their opioid prescription, there is a risk of overdose, which can have serious consequences.

Physical dependence

Physical dependence means that your body has become used to the effects of a drug. It can occur in as little as five days if you are taking opioids continuously or in high-dose infusions during hospital stays. On its own, it is not the same as addiction.

You will usually experience the signs of physical dependence only if you suddenly stop the opioid medication. The signs include uncomfortable 'withdrawal' symptoms such as irritability, shivers, sweating, nausea and stomach pain.

You and your health-care team can prevent or ease withdrawal by planning to reduce your dose little by little or using some other medicines to reduce the unpleasant withdrawal symptoms.


Tolerance occurs when your body needs a higher dose of a drug to get the same effect. It commonly happens if you are taking opioids for a long time, for example using them frequently to treat vaso-occlusive pain.

If you are developing a tolerance to your opioid medication, your health-care team might decide to switch you to a different type of opioid.


Drug addiction is a psychological craving as well as a physical dependence on the drug. People who are addicted to opioids feel unable to stop the medication even after it starts to cause them harm.

When doctors prescribe opioids for pain, they closely control the amount and pattern of use so that they can identify early on if problems are developing.

You may be more at risk of developing an addiction if:

  • your prescription includes daily use
  • you, your parent or your sibling has had an addiction to any substance
  • you experienced early-life trauma (neglect or emotional, physical or sexual abuse)
  • you are taking a fast-acting opioid (one that releases medication into your bloodstream quickly)

Please speak to your health-care team if you or any family members are concerned about your risk of becoming addicted or if you notice that you are craving or misusing your medications.


An overdose means taking so much medication that your thinking and breathing slow down. Overdoses can be very dangerous, even deadly.

The risk of overdose is quite low when opioids are taken over the long term and as prescribed. Overdose risk may increase when opioids are misused.

An overdose is more likely to happen if someone:

  • takes a long-acting opioid much more frequently or in larger doses than prescribed
  • takes a large dose of an opioid along with benzodiazepine (a medication to treat mood and sleep disorders) or other sedating medications (for example, Gravol, Benadryl, antidepressants or gabapentin)
  • uses opioids with recreational drugs or alcohol
  • has kidney or liver disease (these interfere with the body’s ability to eliminate the medication)
  • has a severe sleep disorder, including sleep apnea

To prevent the risk of overdosing:

  • be open with your health-care team about your risk factors for overdosing
  • take the medications exactly as prescribed by your health-care team
  • work with your health-care team to keep track of your medications frequently (making sure you are taking them as prescribed and that the medications are working as they should)
  • tell your health-care team about all the other medications, supplements, alcohol or other drugs that you may be taking in case there are any bad drug interactions
Last updated: September 25th 2023