Ketamine is a powerful anesthetic that usually comes as a colourless, odorless, tasteless liquid, or white powder form.

Also known as: K, Special K, vitamin K

Ketamine has many functions within the brain and body, but primarily promotes the release of the neurotransmitter dopamine within areas of the brain associated with reward/pleasure (Morgan et al., 2012). Ketamine also acts on opioid receptors, contributing to some of the dissociative and pleasurable effects (Morgan et al., 2012).

Generally, the user will experience a sense of dissociation, that may feel like floating, numbness in the body, and feeling withdrawn (Alcohol and Drug Foundation, 2020). The user will also experience increased heart rate and blood pressure (CAMH, 2012a).


Taking large amounts of ketamine or using certain administration routes can produce greater dissociative and/or sedative effects. Taking greater amounts can cause the user to become uncoordinated and lose consciousness. In other instances, the user may fall into a ‘k-hole’ where they have visual experiences that are considered frightening (CAMH, 2012a). Characteristics of a ‘k-hole’ include:

  •       Blurred vision.
  •       Seeing ‘trails’ or intense hallucinations.
  •       Feeling detached from the body.
  •       Feeling ‘near death’.


When ketamine begins to wear off, the user may feel generally low or anxious, experience memory loss and flashbacks of visual experiences/hallucinations (CAMH, 2012a).


While life-threatening adverse effects of ketamine are rare, there are a number of factors that make ketamine use dangerous. Since ketamine can cause the user to become uncoordinated and prevents the user from experiencing pain, the user may be unaware of any serious injuries that occur while using (CAMH, 2012a). In the context of Party & Play/‘chemsex’, gay, bisexual, and queer men being unable to feel pain while using ketamine, may engage in particularly rough sex or anal fisting causing damage to the rectum (AIDS United, 2019).


Using ketamine regularly and/or in large doses can have negative long-term effects. Some common long-term effects of ketamine use are ketamine bladder syndrome, kidney dysfunction, and intense abdominal pain known as ‘k-cramps’ (Morgan et al., 2012).

Ketamine can be administered using a variety of techniques and the effect generally last for 1-2 hours (American Addiction Centers, 2021).



Recreationally, snorting is one of the most common way that Ketamine is used (Morgan et al., 2012). Tools including a rolled piece of paper such as a bill, business card, paper straw or other materials may be used to facilitate inhalation. With 5-15 minutes after use, the user will begin to experience the effects of ketamine.


Service Provider Tip: Remind guys that sharing tools when snorting Ketamine can increase transmission risk of infectious diseases. To encourage safer use, tool sharing should be avoided or tools should be cleaned/disinfected between users.


Ingestion (Oral)

Text: Ketamine can be ingested orally when put into a capsule or a tablet. Ketamine may also be mixed into a drink when in liquid or powder form and ingested. When ketamine is ingested, the user will experience effects 5-30 minutes after use (American Addiction Centers, 2021).


Smoking (Inhalation)

When in powder form, ketamine can be mixed into a cigarette or joint that may contain tobacco and/or cannabis (CAMH, 2012a).


Injection (Intramuscular and Intravenous)

When ketamine is in liquid form, it can be injected both intramuscularly and intravenously. Intravenous injection of ketamine should be avoided as the user may become heavily sedated within seconds after use, increasing risk of adverse effects. When ketamine is injected intramuscularly, the onset of effects occurs approximately 1-5 minutes after use (American Addiction Centers, 2021).


Service Provider Tip: Remind guys that sharing needles can increase transmission risk of infectious diseases. To encourage safer use, sharing needles should be avoided. Guys should only use a needle once as the needle can become blunt, reusing the same needle can damage veins and increase risk of infection.


Booty Bumped (Anal Insertion)

Ketamine may also be booty bumped when in liquid form, using a needless syringe to insert the substance into the rectum.


Service Provider Tip: Booty bumping causes damage to the rectum. Encourage guys to alternate between different administration techniques to give the rectum a chance to heal. Remind guys to avoid sharing syringes or to ensure any materials used for booty bumping have been cleaned/disinfected between users to reduce harms.

Prescribed Substances

Ketamine may produce serious and life-threatening adverse effects when used with certain HIV medications.

HIV Medications

  • Ritonavir and Cobicistat are used to boost the availability of other substances (primarily other HIV medications) in the body by decreasing the breakdown of these substances (Drug and Alcohol Foundation, 2020).
  • Ritonavir and Cobicistat interact with ketamine by increasing the availability of ketamine in the body, leading to adverse effects (Lee et al., 2021).
  • Interactions with Ketamine have been observed Cobicistat-Boosted Elvitegravir regimen (Lee et al., 2021).
  • There significant potential for the ketamine to interact with additional HIV medications including Atazanavir, Nevirapine, and Efavirenz (Lee et al., 2021).


Recreational Substances

When ketamine is used with other recreational substances, this can alter the intended effects of certain substances and increase risk of adverse effects.


  • Ketamine can dull the effects of alcohol, causing the user to consume large amounts of alcohol, leading to alcohol poisoning or other serious and life-threatening effect (Alcohol and Drug Foundation, 2020).



  • When ketamine is used with stimulant drugs like cocaine or crystal methamphetamine, this increases risk of cardiovascular adverse effects including heart attack (Morgan et al., 2012).
  • Using ketamine with MDMA may elevate blood pressure to dangerous levels (Morgan et al., 2012).



  • Ketamine can dull the effects of opiates, leading overuse of opiates and possible opiate overdose (Alcohol and Drug Foundation, 2020).

Recently, Canada passed the “Good Samaritan Drug Overdose Act.” This means that if police attend a 911 call for an overdose and there are drugs present, anyone in attendance is protected against simple drug possession charges, even if they’re on probation or parole. See this helpful info by the Canadian HIV/AIDS Legal Network. You can download a PDF of it [here].

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