Pet allergies—nothing to sneeze at
Allergies affect people of all ages and can produce a variety of symptoms ranging from mild inconveniences such as red itchy eyes on one end of the scale all the way up to full blown anaphylactic reactions that can affect breathing and be life-threatening on the other end. Most of us pet owners know too well that some people are sometimes prevented from visiting us because they are allergic to our pets. My brother recently developed a cat allergy and he stopped coming over to visit until he found a temporary solution in the form of an antihistamine. After trying a variety of different medications he found one called loratadine, which is an antihistamine that works temporarily to suppress allergy symptoms.
The most common antihistamine that is used for allergies, however, is called diphenhydramine (Benadryl). This drug is extremely effective at suppressing the allergy symptoms, but it does have sedating properties. Most people who take diphenhydramine quickly find that their sneezing is replaced by yawning, neither of which is good to have while playing board games with the family. Loratadine (Claritin) on the other hand does a wonderful job at suppressing allergies but does not cause much drowsiness. Other antihistamines for humans include drugs such as cetirizine (Zyrtec), Chlorpheniramine, Desloratidine (Clarinex), and some others. Some of these have longer action, and some cause less drowsiness. Since product selection between these antihistamines could involve many factors including the potential of drug-drug interactions, it is extremely important to consult with a doctor or pharmacist before initiating therapy.
What about our pets themselves, do they suffer from allergies? Yes, most people don’t realize how prevalent it is for a dog or cat to be allergic to something in or around the house, a particular medication, an insect bite, a chemical, or even his best friend – man! Yes there have been reports of dogs being allergic to their owners, requiring a procedure known as desensitization to attempt and reverse that sensitivity. Most allergies however do not require lengthy medical procedures but can be managed at home with some guidance.
When a pet is exposed to whatever is causing the allergy, a chemical called histamine is released. Histamine circulating in the blood is what causes the symptoms such as the sneezing or itching that we identify as an allergic reaction. In order to block the effects of this histamine, an antihistamine is generally used. The most common and effective antihistamine is called diphenhydramine (Benadryl). As mentioned earlier, humans generally choose a different antihistamine because of the sedating properties associated with diphenhydramine. When I need to treat my pet for allergy symptoms, however, I almost always select diphenhydramine.
Diphenhydramine not only works best at suppressing the allergy symptoms but it’s generally the least expensive of all the other treatments. Discovered in the early 1940s by professor Rieveschl, this drug was the first FDA approved antihistamine, and has had a huge influence on the way allergy has been treated since. It is interesting to note that diphenhydramine is also the “forefather” of the antidepressants such as fluoxetine (Prozac) and the other serotonin reuptake inhibitors. The discovery of this drug has been one of the most important events in the practice of medicine this century, along with the discovery of antibiotics such as penicillin.
Although diphenhydramine is not FDA approved for use in veterinary medicine, it is a commonly accepted practice to use this medication in dogs and cats. The usual dose is around 1mg per pound every 8 to 12 hours. The potential for diphenhydramine to cause drowsiness is not usually a problem in pets, but using it with other central nervous system depressants such as tranquilizers or barbiturates should be avoided. This drug should also not be used in pregnant of nursing animals, in animals that have glaucoma, urinary obstruction, or high blood pressure. Although diphenhydramine may be purchased without a prescription, it is always best to consult with your veterinarian and pharmacist prior to initiating therapy, especially if the pet is on other medications or has other medical conditions besides just an allergy.
Anytime you are faced with a pet who is suffering from a condition such as an allergy that seemed to develop out of nowhere or seems to be getting worse instead of better, it’s time to make an appointment with the veterinarian. The veterinarian has treatment options that may not be available over the counter. Drugs such as corticosteroids or other medical therapeutic options may be a better choice for some pets. Drugs like prednisone are sometimes prescribed for short periods of time to treat allergies if the symptoms become more unmanageable or unbearable.
As always, if you have a medication related question you can call a 1800PetMeds pharmacist who will be happy to answer those for you.