Some of Britain's drug users now inject mephedrone up to 20 times per day, the annual DrugScope Street Drug Trends Survey has found.
The survey found there has been a rise in the number of people compulsively injecting the 'party drug', which first came to public attention in 2009.
Findings showed that it is not just existing heroin and crack users who inject mephedrone; people who have never injected drugs before, and those who have previously managed to quit drugs, also take the substance with syringes.
In Ireland, some users have had to undergo plastic surgery to repair arm skin damaged by injections. The rise in the number of people injecting is also worrying because of the increased risk of blood-borne viruses, such as hepatitis C.
DrugScope used feedback from drug services, police, drug action teams and service user groups from 20 locations across the UK - providing a broad picture of the current UK drug scene.
Mephedrone's street names include meow meow, bubble, MCAT and plant feeder. Before it was made illegal in 2010, it was sold online and in head shops. It was mainly used by students and people on the club scene.
After it was banned, there was a brief drop in supply and its new illegal status has dissuaded some curious people from trying it.
However, the survey shows more agencies are reporting problems associated with the continued use and availability of mephedrone.
As well as a rise in injecting, reports found users suffer from psychological problems, including paranoia, panic attacks and general loss of control.
Martin Barnes, chief executive of DrugScope, said: "There is no room for complacency on this. With the arrival of drugs such as mephedrone and the whole array of synthetic cannabis compounds and other new drugs, we may well have a drug scene in transition.
"The rise in mephedrone injecting is especially worrying. Drug treatment agencies need to be able to deal with this new problem and remain alert to the risk of [the number of injectors] increasing.
"With some people engaged in excessive daily injecting, there is a risk of blood born viruses such as hepatitis C, where already over 40 per cent of injecting drug users are infected.
"With so many serious problems now related to mephedrone use, to continue to describe it as a 'party' or 'club drug' risks downplaying the harms associated with its use".
Barnes did note, however, that generally there has been a decline in overall drug use in the UK, with more people recovering after drug treatment.
Other findings from the survey show there has been a fall in the quality of heroin and a rise in drugs being sold on the internet.
Another noticeable trend is the importation of illegal prescription drugs, with diazepam-type tranquilliser drugs and pain killer Tramadol being more widely used and available.