Benadryl for Dogs

About a month ago my 26 pound almost 4-year old Boston Terrier started having allergy symptoms (runny nose, watery eyes that led to facial irritation, itching, etc).  I called the vet and he said it was okay to give him 25mg benadryl twice a day for allergies.  
But now I'm wondering, since it's been a few weeks--is it safe to give bendaryl to a dog daily for long periods of time?  If he's anything like me his allergies will last through the summer at least, but I don't want to harm him by giving him benadryl for months straight.
Thanks!

[Jaybay]

As far as I'm aware, benadry is safe for quite a long time in dogs.  The general doggy dosage is 1 mg/ per pound, so that's what your vet has prescribed - most people tend to go too low on the dosage. Using it for only the summer months should be no problem at all.  I had a dog who needed it a good 8 months or more of every year and it never caused any trouble.  Hope it works well for your Bostie!

[stilltired]

Thanks for the response!  He's been doing better, though still waking up every morning with runny eyes, but at least the Benadryl twice daily isn't making him sedated all day.  I'd feel terrible if it was constantly knocking him out.  (Though us Boston owners know they have so much energy there's not much that can take it away!)