Securing dogs at campsite plus flea & tic control

Frontline worked fantastic for us for years. Recently on advice of our Vet my wife changed to another product. In my aging "crochety old man" suspicions, I found out that Frontline not to long ago switched from only being available from veterinarians to being available over-the-counter, at much lower cost. Then suddenly Frontline is "not as effective anymore". Hmmm....