Opioids, stimulants and more

Last revised: May 13, 2024

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Opioids are a family of drugs that are primarily used to manage pain. Some examples of opioids are hydromorphone (Dilaudid), morphine, oxycodone (OxyContin), heroin, and fentanyl.

Effects of opioids include:

  • Slow heart rate
  • Shallow breathing
  • Drowsiness
  • Feeling like you might pass out

Both prescription opioids and unregulated opioids can cause overdoses.

There is no easy way to know what is in substances from an unregulated supply. Any unregulated drug may be contaminated with an opioid.

To learn more about opioids, how to identify and respond to an overdose, and local harm reduction services visit StopOverdoseOttawa.ca.

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Fentanyl is an opioid that is much more toxic than most other opioids. Opioids include drugs like heroin, morphine, fentanyl, methadone and codeine.

Fentanyl is usually prescribed in a patch form as a painkiller. It is around 50 to 100 times more toxic than morphine. This makes the risk of accidental overdose much higher.

There are also different illicit fentanyls being made and sold. This illicit fentanyl is often made as a powder and mixed with other drugs (like heroin, cocaine or crack). It is also being pressed into pills made to look like other prescription pills (like OxyContin, 80s or Percocet) or other pills including speed. It may be in drugs that are in powder, liquid or pill form.

What's the risk with fentanyl?

When fentanyl is mixed with other opioids, alcohol, benzodiazepines, or stimulants like cocaine, it increases the risk of accidental overdose.

Illicit fentanyl is much more toxic than other pharmaceutical-grade opioids. There is no easy way to know if fentanyl is in the drugs you are using. You can't see it, smell it or taste it. Any drug can be cut (mixed) with fentanyl. Even a very small amount can cause an overdose.

When you are getting drugs from anywhere other than a pharmacy or medical professional, like from a friend, ordering online, or a dealer, there is no way to be sure exactly what is in them or how toxic they may be.  

It's important to know that drugs other than fentanyl can also cause an overdose! 

Check out our tips on overdose prevention and naloxone to reduce your risk!
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Carfentanil is an opioid that is used by veterinarians for very large animals like elephants. It is not for human use. It is approximately 100 times more toxic than fentanyl and 10,000 times more toxic than morphine. This means carfentanil can be deadly in extremely small amounts.

Carfentanil is being mixed in to other illicit drugs like heroin and counterfeit pills made to look like prescription opioids (including green pills stamped 'CDN' on one side and '80' on the other). There is no easy way to know if carfentanil is in the drugs you are using. You can't see it, smell it or taste it. It is extremely toxic and a very small amount can cause an overdose or even death.
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Benzodiazepines, or “benzos”, are substances that can slow down brain activity. They can change the way people think, move, speak, and breathe. Benzodiazepines can help with sleep problems, anxiety, epilepsy/seizures, and alcohol withdrawal. They are some of the most prescribed drugs in the world. Some prescription benzodiazepines are Clonazepam (Rivotril), Alprazolam (Xanax), Lorazepam (Ativan), and Diazepam (Valium).

Benzodiazepine Factsheet (pdf - 187 KB)

Non-prescription benzodiazepines

Benzodiazepines and substances like benzodiazepines are being found in the unregulated drug supply in Ontario. They can be “cut” (mixed) into opioids and other drugs that are sold in the unregulated supply. Some examples are etizolam, flualprazolam, and flubromazolam.

Symptoms of benzodiazepine toxicity and overdose can be:

  • Extreme sleepiness or passing out
  • Dizziness, poor balance, and poor movement control
  • Slurred speech
  • Memory loss
  • Loss of consciousness or “blackouts”

These symptoms can last for hours.

How to respond to an opioid and benzodiazepine toxicity or overdose

When people take benzodiazepines and opioids at the same time, they have a higher chance of overdosing. Naloxone can reverse an opioid overdose, but it has no effect on benzodiazepines. If you think someone has overdosed or they are not responding to you, follow these steps on how to respond to an overdose.

If the person starts breathing on their own, put them in the recovery position. If you must leave the person at any time, put them in the recovery position. The recovery position helps keep a person’s airway open so they can breathe. It can also stop them from choking on vomit or spit.

Individuals who use drugs are reminded to follow these tips on how to reduce your risk

Increased risk of injury, violence, theft

Benzodiazepines can cause memory loss and “blackouts” or loss of consciousness. This can put people at risk of injury, violence (including sexual violence), and theft. Call 9-1-1 if you are in danger and need emergency services.

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Xylazine is a medication used by veterinarians for sedation, muscle relaxation, and pain relief for animals. It is not approved for human use.  

Xylazine is typically present with opioids, benzodiazepines, and other substances in the unregulated drug supply. It is sometimes referred to as “tranq” or “tranq dope” when mixed with fentanyl.

Most xylazine use is unintentional, meaning it is usually cut (or mixed) into unregulated drugs. Xylazine’s presence in the unregulated supply in Canada is increasing. 

Possible harmful effects from xylazine include: 

  • Sedation, drowsiness, fatigue 
  • Extended “blackouts” or memory loss 
  • Difficulty moving, slurred speech 
  • Confusion, dizziness 
  • Severe skin lesions, such as ulcers or abscesses 
  • Slowed or irregular breathing (or not breathing at all) 
  • Low blood pressure, slower and/or irregular heart rate 
  • Coma or death 

It is important to be aware that: 

  • Sedation, memory loss and blackouts from xylazine can last for hours, putting put people and their belongings in vulnerable situations (at risk of injury, violence, theft). 
  • Xylazine can add to the effects of other substances that affect breathing like opioids, benzodiazepines, and alcohol, increasing the risk of overdose.  
  • Xylazine can also be mixed with stimulants (such as cocaine or methamphetamine) in the unregulated supply. 
  • Xylazine can affect a person’s ability to feel pain or discomfort and may put people at risk for injury and accidents including frostbite, sunburn, and heat illness. 

Skin wounds related to xylazine

  • Xylazine can cause skin lesions that may appear anywhere on the body. 
  • These lesions tend to appear faster and heal slower than other wounds.  
  • If left untreated, wounds can become severely infected. 
  • It is important to seek medical care for unusual skin lesions as soon as possible.  

How to respond to an overdose involving xylazine 

  • In all cases of suspected overdose, call 9-1-1 and follow the 5 steps to save a life
  • Give naloxone (learn how to access free naloxone). Naloxone will not have an effect on non-opioid substances like xylazine, but xylazine can be cut (mixed) with other drugs like opioids. If an opioid is present, naloxone can temporarily reverse the effects of an opioid overdose. It is hard to know if opioids are also present, so give naloxone. Naloxone can be safely given to people who have taken non-opioid drugs (like xylazine or benzos).
  • Perform chest compressions and/or rescue breathing, or cardiopulmonary resuscitation (CPR) as needed.
  • Always stay with the person until emergency help arrives. It’s important to know that after being giving naloxone, a person might continue to experience sedation, drowsiness, blackouts or memory loss, even if breathing has returned to normal. The Good Samaritan Drug Overdose Act provides some legal protection for people seeking emergency support during an overdose. 
Individuals who use drugs are reminded to follow these tips on how to reduce your risk
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Stimulants (e.g., cocaine, speed, crystal meth, MDMA/ecstasy)

Stimulants, sometimes called “uppers”, are substances (drugs) that speed up the nervous system. They often come in pill/tablet, capsule or powder form. Some examples of stimulants are cocaine, MDMA (ecstasy or molly), and amphetamines.

Know the signs of a possible stimulant overdose:

  • Rapid pulse
  • Skin feels hot, excessive sweating
  • Chest pain
  • Headache or dizziness
  • Psychological distress (anxiety, panic, confusion, agitation, erratic behaviour, hallucinations, psychosis)
  • Seizures (rigid, jerking limbs, foaming at the mouth)
  • Vomiting
  • Collapse, loss of consciousness

An overdose is a medical emergency. Call 9-1-1 immediately, and stay with the person if it is safe to do so.

Help them remain calm and relaxed in a safe, quiet, dark space if possible. Apply ice to the back of the person’s neck and encourage them to drink water if they are conscious and able to swallow.

If in doubt, give naloxone. Party drugs can be cut with fentanyl or carfentanil. For more information, visit the Centre for Addiction and Mental Health (CAMH) website.


Nitazenes (ny-TAH-zeenz) are opioids that can be more toxic than fentanyl. They were first found in Canada’s unregulated drug supply in 2019, and in Ontario in 2021. Nitazenes are not approved for clinical use.

Synthetic nitazene opioids are being “cut” (mixed) into Ontario’s unregulated supply. In 2024, an increase in the presence of nitazenes has been found in opioids expected to be oxycodone (OxyContin), hydromorphone (Dilaudid), hydrocodone and Percocet (Toronto’s Drug Checking Service):  

  • N-desethyl etonitazene (considered up to 10 times more toxic than fentanyl)
  • Protonitazepyne (considered more than 20 times more toxic than fentanyl)

Nitazenes factsheet (pdf - 299 KB)

Be aware: 

  • Nitazene opioids can increase the risk of overdose, especially for individuals who have lower opioid tolerances or for people who do not use fentanyl.
  • Nitazenes are often present with other depressant substances, such as benzodiazepine-related drugs and veterinary tranquilizers. This increases the risk of slow, irregular, or stopped breathing, and decreases in blood pressure and heart rate.
  • Naloxone should be used in a suspected overdose and may temporarily reverse the effects of nitazene opioids. Continue to follow the The 5 Steps to Respond to an Opioid Overdose.

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Medetomidine and Dexmedetomidine

Medetomidine (meh-deh-TOH-mih-deen) is a medication used by veterinarians for animal sedation. Like xylazine, medetomidine is not approved for human use. Dexmedetomidine (deks-meh-deh-TOH-mih-deen) is approved for clinical use including sedation and pain relief in animals and humans. 

Medetomidine/dexmedetomidine* have been found in the unregulated drug supply in Ontario. They can be “cut” (mixed) into opioids and other drugs that are sold in the unregulated supply. 

Medetomidine and Dexmedetomidine factsheet (pdf - 274 KB)

Be aware, both medetomidine and dexmedetomidine: 

  • can cause extreme drowsiness and sedation, especially when present with other depressant substances like opioids, benzodiazepines and xylazine;
  • are being reported together as medetomidine/dexmedetomidine* because it is not currently possible to differentiate between them (Toronto’s Drug Checking Service);
  • can cause slow, irregular, or stopped breathing, and decreases in blood pressure and heart rate;
  • are not opioids, so naloxone will not affect them, but naloxone will work on opioids that may also be present. Naloxone should be used in a suspected overdose. If in doubt, follow the The 5 Steps to Respond to an Opioid Overdose.

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Where to go for help

If you have a friend or family member who uses drugs, you are encouraged to: 

  • Know the signs of an overdose and call 9-1-1 immediately if you witness an overdose. 
  • Carry naloxone – a medication that can temporarily reverse an opioid overdose. 
  • Take the online no-cost Party Safer course and get a certificate. Learn about commonly used substances, how to ID an OD and access naloxone, and get information on mental health, addictions, and substance use health supports and services.

For more information on resources and services, visit our Mental Health, Addictions and Substance Use Health Services and Resources webpage.

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