Antihistamines for Dogs

Antihistamines for dogs can be a great treatment method for canines with allergies. Every dog will react differently to antihistamines, so it may be a process of trial and error before relief is found.

Dog Allergies and Antihistamines

Dogs can have allergies to food products, mold and things found in their environment (wool, detergents, etc.). A dog can even have inhalant allergies to pollen, ragweed, or dust. When an allergy has developed, it is not uncommon for a dog to become very itchy, develop hot spots, bald spots, or have a coat that lacks luster.

Up to 30% of dogs with allergies have found much needed relief from these products when used with an Omega 3 fatty acid supplement and avoidance (keeping the dog away from his allergens as much as possible). However, one of the negative effects of antihistamine use for dogs is sedation, a common side effect of these drugs.


Diphenhydramine, also known as Benadryl (its trade name), can be very effective for dogs when used properly. Benadryl can control itching and reactions from a bee sting or another insect bite.

Taking diphenhydramine with other medications can harm a dog, so always tell the vet any other medications a dog may be using. This drug may also be dangerous to dogs that have prostatic disease, glaucoma, cardiovascular disease or hyperthyroidism. Dogs taking Benadryl should only take the medication orally with a pill or capsule; the liquid-form should be avoided.


Hydroxyzine, also called Atarax, is a type of medication that blocks the action of a histamine, the chemical that targets specific receptors in a body and causes an allergic reaction. Atarax can only be purchased from a veterinary clinic to help treat a dog's allergy symptoms, especially itchy skin.

Hydroxyzine is generally safe for dogs to use, but should not be prescribed to dogs with glaucoma, certain heart conditions, high blood pressure, and an enlarged prostrate. This drug can also cause drowsiness in a dog and should not be used with other medications such as tranquilizers, barbiturates or other drugs that have sedative qualities.


Tavist main ingredient is clemastine fumarate. This medication's dose can last for an extended amount of time so a dog owner does not have to administer several doses of medicine to a dog every day. There are two type of Tavist; one contains a decongestant called phenylpropanolamine.

Tavist has many of the same side effects as other antihistamines: sedation and dry mouth. However, when it contains phenylpropanolamine, a dog may experience nervousness.


Seldane was the first antihistamine on the market and was distributed in the 1980's. It caused many heart problems that were sometimes fatal in humans and has caused toxicity in dogs. It is not recommended a dog be given Seldane to treat his allergies.

Many different antihistamines are available to dogs that suffer with allergies. A veterinarian should be consulted if one suspects a dog's itchiness is due to allergies.