It is a class III scheduled drug and is approved for use in hospitals and other medical settings as an anesthetic.
However, it is also a commonly abused "recreational" drug, due to its hallucinogenic, tranquilizing and dissociative effects.
Controversy has arisen about using ketamine "off-label" to treat depression. Off-label uses of drugs are uses that are not approved by the the United States, (U.S.) Food and Drug Administration (FDA).
Ketamine is safe to use in controlled, medical practice, but it has abuse potential. Used outside the approved limits, its adverse mental and physical health effects can be hazardous. Prolonged use can lead to tolerance and psychological addiction.
Here are some key points about ketamine. More detail is in the main article.
- Ketamine is similar in structure to phencyclidine (PCP), and it causes a trance-like state and a sense of disconnection from the environment.
- It is the most widely used anesthetic in veterinary medicine and is used for some surgical procedures in humans.
- It is considered a "club drug," like ecstasy, and it has been abused as a date-rape drug.
- Ketamine should only be used as prescribed by a doctor.
What is ketamine?
Ketamine can produce feelings of dissociation when used as a drug of abuse.
Ketamine belongs to a class of drugs known as dissociative anesthetics. It is also known as Ketalar, Ketanest, and Ketaset.
Other drugs in this category include the hallucinogen, phencyclidine (PCP), dextromethorphan (DXM), and nitrous oxide, or laughing gas.
These types of drugs can make a person feel detached from sensations and surroundings, as if they are floating outside their body.
Ketamine is most often used in veterinary medicine. In humans, it can induce and maintain general anesthesia before, during, and after surgery.
For medical purposes, ketamine is either injected into a muscle or given through an intravenous (IV) line.
It is considered safe as an anesthetic, because it does not reduce blood pressure or lower the breathing rate.
The fact that it does not need an electricity supply, oxygen, or highly trained staff makes it a suitable option in less wealthy countries and in disaster zones.
In human medical practice, it is used in procedures such as:
- cardiac catheterization
- skin grafts
- orthopedic procedures
- diagnostic procedures on the eye, ear, nose, and throat
- minor surgical interventions, such as dental extractions
It has been used in a hospital setting to control seizures in patients with status epilepticus (SE), a type of epilepsy that can lead to brain damage and death. However, researchers point out that ketamine is normally used for this purpose after 5 to 6 other options have proven ineffective.
It is also an analgesic, and, in lower doses, it can relieve pain.
Researchers are looking into other possible medical uses of ketamine, particularly in the areas of treatment-resistant depression, suicide prevention, and substance use disorders. However, this use is controversial.
Researchers for the American Psychological Association (APA) noted in April 2017 that a number of doctors prescribe ketamine "off-label," for people with treatment-resistant depression.
However, they caution:
"While ketamine may be beneficial to some patients with mood disorders, it is important to consider the limitations of the available data and the potential risk associated with the drug when considering the treatment option."
The FDA has not yet approved it for treating depression.
In a study published in BMC Medical Ethics, researchers urge doctors to "minimize the risk to patients" by considering carefully the evidence before prescribing ketamine off-label for patients to treat depression and prevent suicide.
Citing "questionable practice" regarding the prescription of ketamine, they point out that there is not enough evidence to prove that ketamine is safe, and that some studies supporting its use have not been sufficiently rigorous in terms of research ethics.
They call for open debate, more research, and for doctors to try all other options first, before prescribing ketamine.
The National Institutes of Health (NIH) are currently supporting research into whether ketamine may help people with treatment-resistant depression.
Ketamine use can have a wide variety of adverse effects, including:
- changes in perceptions of color or sound
- hallucinations, confusion, and delirium
- dissociation from body or identity
- difficulty thinking or learning
- dilated pupils and changes in eyesight
- inability to control eye movements
- involuntary muscle movements and muscle stiffness
- slurred speech
- slow heart beat
- behavioral changes
- increased pressure in the eyes and brain
When used as an anesthetic in humans, doctors combine it with another drug to prevent hallucinations.
Ketamine is considered relatively safe in medical settings, because it does not affect the protective airway reflexes, and it does not depress the circulatory system, as other anesthetic medications do.
However, some patients have reported disturbing sensations when awakening from ketamine anesthesia.
Ketamine can cause an increase in blood pressure and intracranial pressure, or pressure in the brain.
People with the following conditions cannot receive ketamine for medical purposes:
It is used with caution in those with:
- coronary artery disease
- increased blood pressure
- thyroid disease
- chronic alcohol addiction
- acute alcohol intoxication
- chest pain
- mental illness
These effects may be stronger in people aged over 65 years.
Some people may have an allergy to the ingredients. Patients with any type of allergy should tell their doctor before using any medication.
Anyone who is using this drug for therapeutic purposes on a regular basis should have regular blood pressure checks.
As a drug of abuse
Ketamine is most often used in the dance club setting as a party drug. It produces an abrupt high that lasts for about an hour. Users report euphoria, along with feelings of floating and other "out of body" sensations. Hallucinations, similar to those experienced with LSD, are common.
In 2014, 1.4 percent of 12th graders reported using ketamine for recreational purposes. This was down from 2002, when 2.6 percent reported using it.
Street names include:
- Cat Valium
- Special K
- Vitamin K
- The horse tranquilizer
- Super K
It is taken orally as a pill, snorted, smoked with tobacco or marijuana, or mixed into drinks. Most often, it is cooked into a white powder for snorting. Taken orally, it can cause severe nausea and vomiting.
Regardless of how it is ingested, its effects begin within a few minutes and last for less than an hour.
Higher doses can produce more intense effects known as being in the "K-hole," where users become unable to move or communicate and feel very far away from their body.
Some users seek out this type of transcendental experience, while others find it terrifying and consider it an adverse effect.
Unwanted effects include:
- impaired motor function
- high blood pressure
- respiratory problems
As the user can become oblivious to their environment, ketamine abuse puts the person at risk of accidental injury to themselves and vulnerable to assault by others.
Problems with co-ordination, judgment, and the physical senses can continue for up to 24 hours. If an individual is using ketamine in a recreational setting, a sober friend should remain with them to ensure their safety.
Long-term effects include bladder and kidney problems, stomach pain, and memory loss.
If addiction and dependence develop, there is also a risk of depression.
Frequent, illegal use of ketamine can lead to serious mental disorders and major physical harm to the bladder, known as ketamine-induced ulcerative cystitis.
Ketamine and alcohol
Ketamine toxicity alone is unlikely to lead to death, according to the WHO. However, combining it with other substances, such as alcohol, can increase the sedative effects, possibly leading to a fatal overdose.
In the U.S., 1,550 emergency department (ED) visits were due to illegal ketamine use, and 71.5 percent of these also involved alcohol.
The risk of overdose is high, because, for a recreational user, there is only a slight difference in dosage between obtaining the drug's desired effects and an overdose.
Chronic users have been known to "binge" their ketamine use in an attempt to experience again the dissociative, euphoric effects of their early first use.
The complications of long-term use can be fatal.
A final word
Ketamine is an anesthetic drug, used in human and veterinary medicine. It is important to distinguish the valid medical uses from the non-medical, recreational use of the drug.
When properly administered by a trained medical professional, ketamine is a safe and valuable medication.
Used in recreational settings, however, ketamine abuse can produce unpredictable physical and mental health results. In the long term, it can lead to psychological damage and, in some cases, death.
Any drug use should be prescribed by a doctor who knows the patient's full medical history.