Many people are surprised to learn that dogs can be susceptible to allergies and need an antihistamine: Dogs are often allergic to pollen or dust. Less commonly known still is the fact that dogs can be treated for allergies with the over the counter antihistamine diphenhydramine (e.g. Benadryl) which is primarily intended for human use. That having been said, if you believe your dog has an allergy, you should, of course, first consult with a veterinarian before giving your dog an antihistamine, as it is not indicated for dogs with a number of conditions.
Uses Antihistamines with Dogs
In addition to treating allergies, an antihistamine can also be very useful in treating dogs for a number of conditions such as insomnia, motion sickness, and particularly bee and hornet stings. Consult with your vet to ensure it is safe to give your particular dog antihistamine, but if it is, be sure to add antihistamine to your doggy first aid kit.
Dog Antihistamine Side Effects
As with many medications, an antihistamine can have side effects in dogs but these are usually minor and are well understood. The most common side effect of antihistamine in dogs is drowsiness; but unless your dog drives or operates heavy machinery, this can be positive. Other side effects can include dizziness, dry mouth, restlessness and irritability, to name a few. As always, you should report any unusual behavior to your vet.
What to Know with Dog Antihistamine Treatment
In all cases, prior to administering an antihistamine to your dog you should: know the weight of your dog; ensure that the only active ingredient present is the antihistamine diphenhydramine and be sure of the amount present in each tablet or, in the case of liquid suspensions, the amount per fluid ounce, etc. Once you know these variables, you will be able to calculate the safe dose of antihistamine for your dog. If you do choose to administer the antihistamine in liquid form, it's vital to ensure that there are no other medications in the solution. Cold and flu medications are therefore not an option and most vets recommend Children's Benadryl which is alcohol and sugar free and is easier to give an accurate dose to smaller dogs.
Dog Antihistamine Dose Standards
Assuming you have consulted with a vet, the normal dose of antihistamine for a dog is 1 milligram of antihistamine per pound of body weight every 8 hours. If your dog weighs 50 lbs, you could therefore give it up to 50 milligrams of antihistamine every 8 hours. While this may seem like a large dose of antihistamine in comparison to human dosage rates, antihistamine is less effective in dogs than in humans; these larger doses of antihistamine are therefore perfectly safe for dogs. Be aware that while it would be extremely difficult to administer a lethal dose of antihistamine to a dog, do not exceed the dosage rate of 1 milligram of antihistamine per pound of body weight per 8 hours. Check with your vet if you feel unsure about the dose or notice any unusual behavior in your dog after treatment.