A therapeutic amount of ketamine, when appropriately administered by a doctor, will leave a patient feeling peaceful and relaxed. Patients will also feel immobility, forgetfulness, and pain alleviation while under anesthesia.
Ketamine abuse for recreational purposes can be physically dangerous and provide a number of risks to the user, especially at larger dosages. A "K-hole" is an unpleasant experience marked by strong visual and aural hallucinations as well as a scary disconnection from reality in those who take a high enough dose of ketamine.
The consumption of the drug determines the time the effects of it will appear. Oral administration takes 15-20 minutes to generate effects, whereas snorting takes 5-10 minutes.
After injection, the effects last 30-45 minutes, 45-60 minutes after snorting, and 1-2 hours after oral intake. Because ketamine has a short half-life, some people take it in a binge cycle, in which they continually use it to become high and then re-administer it when they fall.