I'm sorry but abusing or drugging a cat isn't going to solve the spraying issue. You need to figure out why it's spraying.
First off its a female cat. Female cats aren't as likely to mark territory as males. I've seen females spray when other cats have come in the house for a visit or after the addition of another cat into the house.
Another possibility for spraying is urinary tract infections or kidney problems. When you bring her in to get spayed you can have the vet test for the possibility of underlying health issues.
The last cause, and the most frequent is the cat box not getting changed often enough. Personally, I wouldn't want to have to walk in my own "stuff" to go to the bathroom. Once she finds another location to relieve herself, the scent is left behind and she will use it as a spot that she's used before.
Cutting the scent so SHE can't smell it is the tricky part. My mom showed Burmese when I was a kid and I learned that vinegar neutralized it. Because I hated the house smelling like we just got done making Easter eggs as a kid I've tried countless products on the market. They pretty much cut the odor that we smell, but fail to eliminate it so the cat doesn't.
In my opinion, spaying her will not solve the spraying issue. It will, however, solve other equally negative issues such as screeching at all hours when she's in heat and attracting male cats to the house for cat fights in the front yard in hopes that she'll get out and get to breed with her. Keep the appointment and have the vet help solve the problem.
Good luck!
