We also used Frontline Plus for many years and were advised by our vet that they are seeing resistance in fleas & ticks because the product has been used for so long. ...
...Just as an FYI for anyone who might be interested -- There's a new Frontline product available in the southern states called Tritak. It looks like it contains an extra ingredient(cyphenothrin)
over what Frontline Plus has.......
resistance to cyphenothrin is widespread
and can be very high in dog and cat fleas (Ctenocephalides spp). As a consequence, products with cyphenothrin may not achieve the expected efficacy. The same applies to all other 'synthetic' pyrethroids (e.g. cypermethrin, deltamethrin, flumethrin, etc.).....""
