Are Antihistamines Safe For Dogs?
Antihistamines are drugs that are used for the ongoing treatment of allergies. Their use is not frequent in dogs, but they exist within veterinary medicine.
Due to its widespread use in humans, it is common to wonder: Are these types of drugs safe for dogs? As always, the one who will have to dictate the treatment to follow will be the veterinarian, but here we leave you some information about antihistamines that will reassure all guardians of dogs with allergies.
What is histamine?
As its name indicates, the antihistamine has an action on histamine. Histamine is a molecule released by the mammalian immune system in allergy processes and has a local reaction. It also performs other functions in the bloodstream and nervous system.
In the case of allergies, histamine participates in hypersensitivity reactions to an allergen (grass pollen, dust, some type of food …)
- Produces tissue inflammation. It increases blood volume by vasodilation, allows fluid to escape to the detected area and attracts leukocytes. The inflammation causes redness, heat, edema and itching.
- Regulates sleep. It acts in the nervous system as a neurotransmitter. Histamine prolongs wakefulness and reduces sleep and works in the opposite way to melatonin.
Types of antihistamines for dogs How do they work?
Anti-histamine drugs are divided into three different types and each palliate their effects differently:
- Physiological antagonists. They are chemical compounds that produce the opposite physiological effects of histamine: adrenaline, ephedrine, xanthine …
- Histamine release inhibitors. They reduce the consequences of histamine on the body, preventing its release into the bloodstream.
- Competitive drug antagonists or antihistamines. They are drugs that occupy histamine receptors, so that it cannot act on its cellular targets. Within this category there are three different types of antihistamines in dogs, depending on the type of receptor with which they interact: H1, H2 and H3.
Are antihistamines safe for dogs?
Antihistamines for dogs are safe as long as they are prescribed correctly by a veterinarian and the pet owner follows their directions. Stopping the symptoms caused by a large release of histamine (typical of allergic reactions) and protecting the gastrointestinal mucosa are its main effects.
H1 antihistamines act on histamine H1 receptors, responsible for vasodilation, vascular permeability and contraction of the bronchial and intestinal muscle. These types of drugs are used in allergic reactions and anaphylactic shock. Also when there is itching, hives, dermatitis, eczema, insect bites … in combination with other drugs.
Histamine H 2 receptors regulate the secretion of HCl in the stomach and have a cardiac stimulating effect. Antihistamines antagonists of this receptor are used to alleviate the effects on the digestive system, specifically, gastroduodenal ulcers and gastritis.
H 2 receptor antagonist antihistamines are used by having an antisecretory effect until the gastric protective barrier is restored.
Side Effects of Antihistamines in Dogs
Antihistamines are usually prescribed together with other medications to treat symptoms caused by allergies, but the disappearance of the itch, one of the most striking symptoms in these cases, is not immediate. Its effect is enhanced by adding omega -3 or omega-6 acids to the dog’s usual diet.
These drugs can have certain side effects, which are reported by the veterinarian prior to use. Drowsiness is the main side effect of antihistamines, but rarer ones can appear:
- Anorexy.
- Vomiting
- Diarrhea.
- Increased itching.
It is very important that a veterinarian recommends the use of antihistamines. Do not medicate the dog on your own, as they must be used with caution in animals with pregnancy, liver disease, seizures, urinary retention, glaucoma, and gastrointestinal atony.
There are alternatives to using antihistamines, either as an oral medication or as a topical treatment, but you should always consult your vet before applying them.
