No two dogs, like no two people are the same, so individual sensitivities to any drug can occur in any dog. Ours, for instance, had a terrible reaction to Trifexis, and a reaction to Nexgard, though not as severe as to Trifexis. She does well with Frontline+ which I really only use during the hot summer months. So there is no absolute answer to your question, you will have to try different preventatives to see what your dogs reaction will be.