The optimal dose of alprazolam for most dogs that have any element of panic to their response is 0.02 to 0.04 mg/kg. Because alprazolam comes in 0.25-, 0.5-, 1- and 2-mg tablets that are scored, it's easy to find a dose that works for most animals. For a medium-sized dog, starting with an initial 0.25-mg dose is best.