What is a word for taking measures in order to prevent something?

(Or soften the experience, rather)
Next week I have an appointment with the dental hygienist, and since I have had several before in the past years, I know from experience that it’s very likely that I’ll be in pain.
My idea is to take a couple of painkillers, before I go, to hopefully don’t feel it so bad.
How do we call such action?
It’s not preemptive, right?
Or precautious, right?

More important, will this taking-painkillers-before-the-appointment work?

Thanks in advance.