trying to confirm medication for my dog. Meds should be benazepril hcl, 5mg, tablet. Made by Amneal, is white, round, and approximately 2-3 mm in diameter. Marked A on one side and 51 on the other. I found it in one website, but the site stated that it was a 5mm diameter not 2-3mm. Do I have the right pill and if so why is the diameter much smaller?