Hi Doganjo, when we had a rat problem a few years ago, I was similarly worried about our cats, and neighbour's dog. However, when I did the calculations as to the amount needed to kill a rat, and then the number of dead rats a dog or cat would need to eat to get a fatal dose, I satisfied myself that any issues were pretty unlikely, provided the dog couldn't eat the poison itself. Your mileage may vary of course, but that was my own conclusion.
The blocks got rid of the rats very quickly, and since then, we've put bait boxes around the barn etc, and check them regularly. This seems to have prevented any re-infestation.
HTH!