Choosing an Antihistamine for Dogs

Choosing an antihistamine for dogs can be a trial and error process with your vet to make sure you find the most effective antihistamine. The most common antihistamine for multiple breeds is benadryl.

Allergy Development

Allergies take time and lots of exposure to the allergen in order to develop. Many dogs develop allergies between one and three years old, although some may develop when they are six years old. Most allergens are airborne and will get into the body by inhalation. Once inside, the allergen works by causing the immune system to attach to certain tissue mast cells in the skin. This causes a release of aggravating chemicals, one of which is histamine.

A dog might be allergic to pollens, food products or house fleas. If he is allergic to pollen, he might have an allergic reaction just during the three weeks of the year when that pollen is active. If there is a dust mite or flea infestation in his environment, he could be affected year round. Development depends on exposure. If your dog is sneezing and scratching his hair the whole year, his living environment might be the cause.

Allergies can affect all dogs. Terriers such as the Scottish and Cairn; the larger breeds such as Dalmatians and Irish Setters; and English Bulldogs, Pugs and Miniature Schnauzers are particularly susceptible.

Antihistamine Remedies

Since histamine is the chief irritating chemical in allergies, an agent that works against it, such as antihistamine, proves highly effective. The most common antihistamine is benadryl, or diphendyramine. Many dog owners use benadryl as their dog medicine, as it effectively stops itching, reduces swelling and fights airborne allergens. Dog owners and vets recommend a 1mg/lb dose for best results. Make sure the only active ingredient inbenadryl is diphenhydramine. Some other benadryl products such as Benadryl for Colds contains alcohol, which could impede further recovery.

There are other effective antihistamines such as Chlorpheniramine, Clemastine and Hydroxyzine. Chlorpheniramine usually comes in tablets that are administered three times daily. Time release tablets are also available for convenience. Clemastine is a generic antihistamine that pet owners observe is highly effective in treating allergy symptoms and needs to be administered only every 12 hours. Hydroxyzine has been effective in treating skin allergies along with other skin conditions.

Side Effects

When choosing an antihistamine for dogs, consider the side effects as well as the benefits of each different antihistamine. Most medications will cause drowsiness, while others such as Chlorpheniramine might also cause tiredness, lethargy and diarrhea. Since Hydroxyzine is a more aggressive and variegated antihistamine, its side effects range widely from drowsiness to seizures to nausea. Your dog's response to antihistamines will vary, depending on his size and the given dose.

Dog medicine should also be taken in conjunction with a diet that will compliment the antihistamine best. Dogs that eat a diet rich in fatty acids show heightened response to antihistamines.

Finding the right dog medicine will take time as you decide which antihistamine will suit your dog's needs best. Benadryl is a good start since it is proven and its side effects are limited.