Q. it was suggested that I give my rottweiler (175lbs) benadryl a way to calm him so that I can trim his nails...alternative to Vet sedating to cut
DAVID ELBEZE, DVM, MRCVS
A. Well, it really depends on your dog general temper. in some dogs Benadryl could make a dog sleepy, although you would need several tablets in order to maybe achieve that in such a huge dog. in some dogs Benadryl will just not be enough, they will be slightly sleepy but then when you will approach their nails they will wake up completely and will not be sedated at all.
Usually with big dogs, if they walk on concrete every day, they rarely need nail trimming (only the front due claws).
A better alternative to Benadryl would be to get Xanax from your vet. this has better chances to knock him out enough in order to trim his nails.