Government advisers call for ketamine reclassification
10 December 2013 Last updated at 13:48 GMT
The Government's official drugs advisers say ketamine should be reclassified from a Class C to Class B drug.
The horse tranquilliser - which can also be used as an anaesthetic in humans - was found to cause severe damage to the bladder after frequent use.
Val Curran, a Professor of Psycho-pharmacology at University College London, told BBC Radio 5 live's Breakfast: "It's got a very important role in medicine and has been around for 50 years."