Flea meds/shampoos can be pretty toxic and I wouldn't want to subject my dog to both of them at the same time. Plus, grocery store type flea meds are much more toxic than the vet-quality flea meds, so use with caution. I don't use anything but Frontline and Advantage, but there are other vet-quality flea meds, too. You can use BLUE Dawn (only blue, and no other brands) to kill fleas. It's safer than a pesticide shampoo. Leave it on for 5 minutes after lathering so it can kill the fleas.
After any bath you hould wait a couple days before applying topical flea meds, because the meds spread through body oils, and most of the oils will be gone after a bath. It takes a couple days for them to come back. If the flea meds are applied before that, they won't be as effective.