Ketamine produces a combination of stimulant and hallucinogenic effects. It can alter users' perceptions, leaving them feeling detached from themselves and others. It's a dissociative drug, which means it gives a floating, dreamy feeling - as though mind and body have been disconnected. Ket and Special K are the most popular slang terms, and a person who has taken too much of the drug is said to be in a K-hole.

What is ketamine?

It is sold pharmaceutically in an injectable form, as a clear liquid, but most recreational users encounter the drug as a powder. It will typically be cooked by the dealer into a crusty residue (by drying in the oven, microwave, or air), which is then ground to powder. The powder can be snorted as small "bumps" from the end of a key or the corner of a credit card or chopped into lines, like cocaine. It can also be smoked in a joint or a pipe, mixed with tobacco and marijuana, or taken orally, although oral use tends to induce sleepiness without the dissociation most users desire.

Heavy ketamine users prefer to inject the liquid into the leg, which bypasses the liver and is said to produce a smoother high. It has recently been discovered that, if taken frequently, users can become dependant on ket and that sustained use can lead to memory problems and cause severe cystitis in both men and women. "We discovered that ketamine causes serious lacerations to the bladder," says psychopharmacologist Professor Valerie Curran of University College London. "In some cases people have needed to have their entire bladder removed."

How is ketamine made?

Ket is an entirely man-made drug. It's not generally produced illegally as it is too complicated to synthesise, and the chemicals needed to make it are not readily available. Instead, it is obtained from medical or veterinary sources, or brought in from countries where it's not a controlled substance. Before Indian authorities made ketamine harder to buy, much of Britain's ketamine arrived in the UK disguised as rose water. Now users and dealers are more likely to purchase small amounts over the internet.

Where does ketamine come from?

Ketamine was first synthesised in 1962 by Dr Calvin Stevens of Wayne State University, who was researching alternatives to the anaesthetic phencyclidine (PCP or 'angel dust') which had fallen from favour in medical circles because of the unpredictable and often violent effect it had on behaviour.  Stevens worked for Parke-Davis, (now Pfizer), which at the time was America's oldest and largest pharmaceutical company.

During the 1960s and early 1970s ketamine was heavily used on the battlefields of the Vietnam War and is still used in combat situations today. "It provides a strong analgesic, painkilling, effect without affecting the patient's breathing," says Professor Curran. "So it is useful in medical situations where it would be difficult to resuscitate the patient."

How does ketamine reach the streets?

The Independent Drug Monitoring Unit reported that in 2007 there were around 90,000 ketamine users in the UK - a rise of 50% since the year 2000. A January 2009 report for Drugscope revealed that users are taking higher doses of the drug and more people are injecting the substance. According to Drugscope's 2008 Street Drug Trends Survey, the average price of a gram in the UK has fallen from £30 to £20 in the last three years.

Ketamine is currently a Class C drug, on the same level as cannabis. This means that it is illegal to possess or take the drug, and users risk a fine or prison sentence if they are caught with it.

Updated: 08/01/2010

Anne-Marie Payne