Ask your doctor about it. Then, pull this list from Wal-Mart:

http://www.walmart.com/catalog/catalog.gsp?cat=546834

and ask if he'll write a scrip for what you/he think you'll need. At $4 each, they're dirt cheap, and no need to tell your insurance co.

Something everyone here forgot to mention, make sure you write down (preferably while at the physician's office) the route, dose, indication and time you'll need to take these drugs. For example, Keflex is great for skin infections, but not so good if you've been chugging dirty water and have diarrhea. And, are you on the 750mg, 5-day dose, or the 500mg, 7-10 day dose? You'll need to do more than just walk to your pharmacy and fill them up- you NEED to have enough basic medical knowledge to use the drugs effectively.

That being said, if you're bold, ask your physician if there's a book you can buy that will help tell you this stuff if you forget. Some pharm representatives will "give" these types of books to the doctor if he asks, so you might get lucky and get a $200 book for free 9. Otherwise, you might be able to Google each drug and pull the info directly from the manufacturer.

Some good resources I've used in the field or hospital:
-Sanford Guide to Antimicrobial Therapy
-Epocrates (Epocrates.com, free for PDA)
-Physician's Pharmacopia (pricey, HUGE book)
-Some basic pharm texts are better than others, available at book stores by the nursing/weight loss/self-help medical section.
-Some pocket reference books for EMS professionals have real basic pharm info in the back. Also at book stores.

Good luck!