Ketamine is used in medical procedures in powder or liquid form with humans and other animals. It is mainly used for starting and maintaining general anesthesia.
It was first developed in 1962, and already in the 1970s it was used as recreational drug in the USA. After this it quickly spread to Europe, Canada, Asia, and Australia, primarily in the context of raves and parties.
Ketamine produces similar effects to the ones of phencyclidine (PCP). Unlike the other well-known dissociatives, such as PCP but also dextromethorphan (DXM), ketamine is very short-acting with its hallucinatory effects lasting around 60 minutes if snorted or injected and up to 2 hours when ingested.
People usually prefer to snort ketamine, but the drug can also be ingested, for a more intense effect, or directly inject it intramuscular. People usually do not do intravenous injections, since it might be dangerous, and the drug works perfectly just injecting it easily into your muscles.
The effects you have using ketamine are fundamentally different from any other drug, since ketamine belong to the category of the dissociatives. You will have hallucinations, depending on your dosage, but the experience is far from those you might have using classical hallucinogenic such as LSD and mushrooms, or even phenylethylamine such as 2C-B. The dosage is usually between 10 to 100 mg for snorting or intramuscular injections if you want to have light to strong effects. Doses are usually slightly higher if you decide to ingest it.
Some people might experience muscle pain even couple of days after use, if injected intramuscular. Therefore it is suggested to take ketamine using this method only if you are expert with the injection method, otherwise, just snort it or ingest it.
If you ingest it, you might have a lower peak, but a longer duration of the effects. At low doses of ketamine, between 10-30 mg, the hallucinations are only seen if you are in a dark room keeping your eyes closed.
Other reported effects using a low dosage are distortion of the sensory perception, and numbness of your body and muscles. When taking a medium or a high dose, such as 30-100 mg, the effects are similar to a low dosage, but far more intense and obvious, with out of body experiences connection and becoming all in one with the world around you.
At sufficiently high doses (above 100 mg), users may experience what is called the "K-hole", a complete dissociation of your brain from the rest of your body, whose effects are thought to mimic the phenomenology of schizophrenia. Users may experience worlds or dimensions that are ineffable, all the while being completely unaware of their individual identities or the external world. Impressions of the K-hole often include profound distortions in or complete loss of bodily awareness, sensations of floating or falling, euphoria, and total loss of time perception.
Due to these detached, dreamlike states it creates, where the user finds it difficult to move, ketamine has been used as a “date-rape” drug.