I've used frontline on my dog for years-no problems. Several months ago, my vet recommended I change to ProMeris, stating that it was more effective and cheaper. After my third application, my lab almost died. Three hours after the treatment he was salivating uncontrollably. This ceased, but a few hours later he was stumbling and falling. Finally, between 1-2 AM, he started shallow/labored breathing. (No luck contacting the vet.:mad:) I thought I was going to lose him. Ya, this stuff is cheaper, as you don't have to treat a dead dog.
I was on the phone to company customer service at 7 AM. After much prodding and pointed questioning, the girl admitted that they had had "some" similar reports. Since then, I've done internet searches and found that this reaction is not THAT uncommon for ProMeris. However, I've also heard other horror stories about every topical treatment, including frontline.
Bottom line, watch your dog carefully, no matter what you use, but especially if you use ProMeris. As I stated, it took three treatments for him to have a violent reaction, and it was almost fatal.
It's now been six weeks and my lab is still not acting normal. I don't know if I will ever have him back, completely.:mad:

What's the age of your Lab? Hope things get better.

If something happened to my lab I am pretty sure I would be the first SILO member on CNN. You just can't trust anything. Thanks for the info, because if my vet even mentions it I will come unglued.