Some dogs as well. Permethrin based flea prevention caused my healthy dog to become lethargic, labored breathing and over salivation. I washed it off, and he recovered in a few hours, but I've avoided giving him flea control since then. Luckily he has avoided ticks and fleas but I would bring him to the vet if he did pick any up.

https://m.petmd.com/dog/conditions/neurological/c_multi_pyre...