Need an un-bias opinion for this as shit could be stirred if i ask opinions from a mate.

For the next atp i've paid for the tickets for 2 of my mates, not that i've got an abundance of money but i am a nice bloke. However, these two people are mates and one of them is one of my best mates. However, the other one has changed. She came to the last one and it was alright, although she doesn't really give a shit about the music. She was more bothered about getting fucked in both senses. Since, she has turned into a bit of a coke fiend and is just a horrible person when on it.

As im payin £375 for this i want to have a good time but also want my other friend to have a good time and don't want to somehow cause shit between anyone. Do i just deal with it or tell her in the nicest way possible that i don't want her to go?

It's been on my mind for day's now and is pissing me off. So opinions would be nice.