Your medication dose hasn't changed since the 80's, back before I even went to med school.
I write you a new script once a year, that you fax to your mail-order pharmacy.
Normally I see you in January, but you had to move up your appointment since you'll be out of town next month. So you asked me to date your next Tegretol script for January 1, 2010, and you won't send it in until then. Fine. I did just that.
So, after I've given you a post-dated script DON'T FAX IT TO YOUR FREAKING PHARMACY WITHIN AN HOUR OF LEAVING MY OFFICE!!!
Now I've got the pharmacist calling, wondering if I'm demented and don't know the date (not an unreasonable thought). I'm pretty sure he doesn't think you have some sort of special time-traveling fax machine at home.
So don't do it again. Put the script on your refrigerator and don't cash it in until January 1, 2010 LIKE YOU TOLD ME YOU WOULD and we'll all be happy.