How can you get opiates out of your system faster?

Time is the only tried and true way. Opiates typically take 3 to 5 days to leave your system, depending on frequency and severity of use. For a drug test, I'd say 6 days, just to be safe.

If you have a drug test in less than 6 days, then call them on the morning of the appointment, tell them you are sick with the flu, and reschedule the test.

Don't let them pressure you into keeping the original appointment. You are so sick, you cannot even stand up without vomiting, so it is simply not possible. They may try to threaten or frighten you into thinking you have to keep the original appointment, but unless this is a parole drug test, there's really nothing they can do about it. If you're sick, you're sick.

And don't let them tell you that you need to provide them with a doctor's note, either. If you are too sick to stand up, then you are too sick to go to the doctor.