Thank you for your question. My name is***** and I have been a small animal veterinarian for 12 years. I am in the US and we may have different flea populations, but my personal experience is that the effectiveness of frontline is slightly less than it was previously.
It is still more effective than any other products on the market if you are applying it monthly.
I have asked the company and they assure me that they are constantly doing testing and they are not finding any resistance in the flea populations that they are testing so it is purely my experience and what clients are telling me.
Do you need the tick control? Because I still think Frontline is the best flea/tick product out there, but if is is just flea control that you need I think Advantage and Comfortis are both slightly more effective.
I meant more effect than many other products, not any other product....
Comfortis is not labeled for cats and they don't tend to like the taste, so I'd try Advantage if the Frontline isn't working for you.
I hope that helps, but if you have additional questions, please let me know.