I used Frontline in GA US, and never had an issue. However, I did talk to my vet and the real issue is improper dosing, treatment and, some animals just get sick from the meds, as they soak into the bloodstream...
But they do work... sometimes...

I found this on the Web .

* 2 tablespoons vegetable or nut oil (almond oil contains sulfur, a repellent in its own right)
* 10 to 25 drops Rose Geranium, or palmerosa essential oil

Combine the ingredients in a glass jar; shake to blend. Makes: 2 tablespoons
Shelf Life: 6 months

Place ONLY a few drops on the dogs collar, and viola... Ticks and fleas should be no more.....

You can also mix the essential oil and water in a spray bottle and spray bedding.....

Something else to try... works for animals and people....

"Skin So Soft" from Avon... Yeah.. I know.. No Avon here... Works great for mosquitos as well. Just rub it on.....

"Listerene" or other mouthwash... Put in a spray bottle with water and spray the pooch down... Not only will it repel critters, your best friend will smell fresh and minty ...