When we just had one kid, it was easy to handle medication dosing - one person (usually me, since I'm the stay-at-home parent) was in charge of medication and keeping track of when the last dose was given. With two kids, the lack of time, and the lack of sleep, my husband's reluctant to wake me up to ask just when was the last time I gave Boo a dose of ibuprofen for his ear infection? And what's his dose again? And am I really giving a coherent, accurate answer when I'm not awake?
I bought a dry-erase board that's designed to go on the inside of a locker, so it has magnets on the back. It hangs out on our refrigerator. The dosages for every medicine that the kids could possibly need is written on it, and when we give one of the kids some medicine, we write the date and time on the dry-erase board. The important thing to remember is to write the date and time on the board just before giving the medication, to ensure you're checking the last medication time before dosing.
Unfortunately, I can't seem to find a link to the dry erase board I bought, and most of the 'magnetic' dry erase boards just seem to accept magnets rather than being magnetic themselves. I would think that magnetic tape could be bought to be stuck to the back of a lightweight dry erase board. The board I bought is really only big enough for two kids worth of medication anyway - if I were this gal, for instance, I'd probably need at least an 11x14 board. (Chris has a fantastic blog, hop on over there if you haven't read it.)