the amitraz (tactic) toxicity is not strictly in small breed dog. Any dog can have it, depending the concentration of the mixture, the user, the amount being absorped. Small breed dog tend to be easier to have this problem because their body surface over body mass is much high than a larger dog. Hence, absoprtion is higher and faster. It will be even more dangerous when there is more open wound, like tick bite, scratching, skin problem... Therefore, amitraz is only best used by trained personnel.

There can be cumulative effect of amitaz in the body especially the body fat and liver. Long term usage can slowly lead to chronic toxicity and irreversible damage.