Users of the drug ketamine should face tougher legal penalties, the government is set to be told.
It's thought the Advisory Council on the Misuse of Drugs (ACMD) will say it should be a Class B rather than a Class C substance.
It would mean maximum prison-terms for users rising from two to five years.
The drug does serious and permanent damage to bladders, with some users needing the organ replaced.
Long-term users in Bristol have been telling Newsbeat how ketamine has affected them.
"Molly", 25, waiting for a bladder-stretching operation
"I'll be able to hold more [urine] and also they'll be able to treat the inside of the bladder, to calm the inflammation down.
"It sounds a bit strange to say you're looking forward to an operation but I'm hoping it'll be the start of an end.
You told us you're not "your typical druggy". What did you mean by that?
"I'm from a good home, I've had a decent upbringing, I'm well presented I guess.
But you also told us you'd be sitting on the floor of...
"Crack dens! Waiting to buy ketamine.
"I'd sit around looking at all the others who lived in these squats, and say 'I'm not like these people'. Now I say 'I'm just like them.'
"I have to go the toilet three times an hour.
"It takes me ages to get started, and it's absolute agony.
A lot of users tell us they get to a point where they've got pains in their waterworks. The temptation is, to keep taking it?
"You're writhing in agony. The only thing that takes that away is ketamine. It's sort of like a vicious cycle.
"I'm actually peeing blood - like sizeable blood clots.
"Also, something that I think ketamine-users will relate to is jelly.
"It looks like parts of your bladder.
"My parents caught me on ketamine, and saw their little girl in such a horrendous state. I beat myself up, having to put my parents through that.
"Ketamine being Class C is completely ridiculous. It's not taken that long for me to completely ruin my bladder."
"Jeff", 28, dubstep MC
"I've seen people have cramps, have hot sweats, not be able to move - and then that night, get back on it.
"I actually need to be able to speak articulately [on stage].
"If I take the drug even a couple of days before I have a show, it's really noticeable in my voice. I'll forget my lines.
"When it's destroying something you love, it's not worth it really.
Why did you start taking it?
"Where I used to live, there was nothing to do at all.
"We had this mentality of really battering whatever substance we had in front of us. K [ketamine] just seemed to be the best substance we had available.
"We really didn't know any of the stigma around it."
Do you think the fact that ketamine is Class C makes people think it is safer than other drugs?
"Definitely. I could see that it should be a class A.
"When you compare it to something like ecstasy, it's ridiculous.
"If you get caught with, say, 25 grams of K [ketamine] you'd get done the same as for that amount of weed [cannabis]. That's ridiculous really."
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