The recommended Benadryl dosage for adult dogs is 1 milligram per pound of body weight every eight hours, according to Veterinary Place. Owners can double the amount if necessary, but they should always consult a veterinarian first since dosages can vary depending on the dog’s breed and medical history.
As there are several variations of the drug on the market, and not all of them are suitable to give to a pet, it is best to use one designed specifically for dogs or recommended by a veterinarian, Veterinary Place states. The formulation must include either diphenhydramine or cetirizine as the active ingredient. The dosage above is for the disphenhydramine variation, which treats canine allergies, anxiety, insomnia and motion sickness. Sleepiness is a common side effect of Benadryl; however, if a dog’s condition worsens significantly or the owner suspects an overdose, he should seek emergency veterinary care immediately.