Advice Needed Urgently

I need something, anything, that will prevent me from losing my voice before we open Richard III tomorrow night.

I came down with pharangytis this morning and the Doctor reckons nothing can be done, but I refuse to believe her.

I don't care how crackpot it is, at this point I'm prepared to try anything.

Does anyone out there have a sure fire remedy, something they have succesfully used in the past?

Melissa