Harm Reduction

Negative physical effects can include:

  • hallucinations
  • blurred vision
  • irrational behaviour
  • seizures
  • breathing difficulties
  • anxiety and racing heart

Ketamine slows reflexes and impairs coordination, so minor accidents like bumping into objects are common. Thanks to its anaesthetic effects, any sense of pain is significantly reduced, and the user may only become aware of these knocks when bruises develop later.

Ketamine severely impairs coordination so no attempt should be made to drive or operate machinery while under its effects.

Users should also be aware of distortions in perception of time and space and even relatively simple tasks such as judging distances and speed (for example crossing a busy road) can be compromised. Several deaths have occurred when people have attempted to swim on ketamine, so care should be taken to avoid bodies of water, even the bath.

Users may also experience nausea and/or vomiting. Oral use is most commonly associated with unpleasant sensations and severe side effects. Regular use, especially in conjunction with alcohol consumption, can cause bladder infections (see 'ketamine bladder' below).

Ketamine is a drug where ‘setting’ needs to be carefully considered, it is prudent to be with friends who are not drug naïve or in an environment that you have no control over.

Ketamine is found as an ‘impurity’ in some ‘ecstasy’ tablets. Due to similarities in appearance, ketamine may also be confused with other drugs such as amphetamine and cocaine, despite the fact that the action of ketamine is very different from pyscho-stimulants. This has resulted in some users having bad experiences as they are not prepared for the effects and there is no dose tolerance between the drug types.

Ketamine has the potential to be both physically and psychologically addictive. Regular users build up tolerance and larger doses are needed to achieve the same effect. Ketamine is more psychologically addictive than the psychedelics, and use can become a daily habit. Repeated long term use can occasionally result in more severe problems like psychosis, or liver and kidney damage. Individuals who use it regularly may find it difficult to stop. It is not wise to discontinue from large doses abruptly and some degree of tailing off towards termination is suggested. When a person attempts to reduce the daily volume of a drug to which they have become dependent, it is clear that there is potential for postponing cessation repeatedly, so setting firm targets and sticking to them is crucial.

Ketamine bladder

Long-term ketamine use has been shown to damage the bladder and urinary tract, causing ‘ketamine cystitis’ or ‘ketamine bladder syndrome’. This manifests itself in symptoms such as urinary frequency, urgency, pressure, pain, incontinence and/or bleeding from the bladder. The aetiology (reasons for damage) are not fully understood, but chronic use can cause ulcers/wounds and stiffening of the bladder walls, which shrink the size of the bladder.


As an increasingly popular club drug, ketamine is often associated with polydrug use (the use of several drugs simultaneously or consecutively). It is most commonly mixed with other popular club drugs, such as ecstasy and cocaine (Calvin Klein or CK is a slang term for this combination). Combining ketamine with alcohol or other depressant drugs is particularly dangerous because it increases the risk of losing consciousness. 

What are the risks of injecting Ketamine & how can you inject more safely?

When ketamine is injected and any injecting equipment is shared (needles, syringes, spoons, filters or other paraphernalia), there is a risk of contracting Hepatitis B and C, HIV (which can lead to AIDS) and other blood-borne diseases. These viruses can be extremely resilient, and normal cleaning will not eliminate them, particularly in the case of Hepatitis, which can live outside the body (in certain circumstances) for up to three months. People who are infected with these viruses usually appear healthy, and may not develop the disease for years. From the moment someone is infected however, they carry the virus in their blood, and can infect others through sexual intercourse (particularly with HIV) and sharing any injecting equipment, even spoons and filters.

Those who inject can protect themselves from HIV/AIDS and Hepatitis by always using clean equipment, obtainable from needle exchanges and some chemists, and not sharing with anyone else. For more information, including harm reduction, se our 'safer injecting' section here.