Ketamine or methoxetamine

Ketamine is a well known drug, widely used in therapy during 50 years. Recreative use of ketamine has, more or less, 15-20 years. In the last 5 years there have been a lot of scientific reports talking about bladder and urinary problems in ketamine users.So, this was an unknown problem until 2005 (more or less), and has been detected after 15-20 years of recreative, intranasal use. In general, it only affects to intensive users. Ketamine dependence is another problem with this drug.

http://www.ncbi.nlm.nih.gov/pubmed/21155941

PCP was used in medicine from 1920 to 1950 and it was finished then because of its adverse side effects, such as hallucinations, mania, delirium, and disorientation. In fact ketamine has its substitute, because it has less adverse effects. PCP has been linked to neurotoxicity in animals, but it is not probably extrapolable to humans.

Additionally, PCP can be lethal in overdose, this event is much less likely with ketamine.Methoxetamine is a very new substance. We don´t know anything about its pharmacological properties and toxicity in humans, although there are reports of problems linked to its use:

http://www.ncbi.nlm.nih.gov/pubmed/23111916

http://www.ncbi.nlm.nih.gov/pubmed/22578175

http://www.ncbi.nlm.nih.gov/pubmed/22205276

http://www.ncbi.nlm.nih.gov/pubmed/23349353

Considering overall risks and benefits, probably ketamine is the safest, most pleasurable and less risky of all dissociatives, although it has it own problems associated indeed.