Diphenhydramine (Benadryl®), cetirizine (Zyrtec®), and loratadine (Claritin®) are commonly used antihistamines that relieve allergy symptoms or counteract allergic reactions. Antihistamines are usually safe but can make some dogs drowsy and others hyperactive.
Benadryl is a great medication for use in dogs with mild-to-moderate allergies. Seasonal allergies, food allergies, environmental allergies, and allergic reactions to snake and insect bites all respond to Benadryl in most cases.
Antihistamines with the active ingredients of diphenhydramine, chlorpheniramine, cetirizine, clemastine or loratadine are usually safe for most healthy adult dogs. Hydroxyzine is another dog-safe antihistamine and one of the most effective available, but it's only available on prescription.
Best treatment: Antihistamines
Antihistamines are commonly used to treat dog allergies. Their histamine-blocking quality tackles airborne allergens and reduces symptoms in your pup. The safest over-the-counter options for your dog include Benadryl, Zyrtec, Claritin, and Allegra.
Zyrtec is an over-the-counter human allergy medication sometimes given to dogs with atopic dermatitis or mild to moderate environmental allergies. Vets may recommend Zyrtec for dogs who scratch excessively, are sensitive to insect bites, or have dermatitis.
You can safely give Zyrtec to your dog up to 20 mg per day.
DO NOT USE ALLEGRA D IN PETS. Fexofenadine is also available an oral suspension that contains xylitol (NOTE: Xylitol may be toxic in dogs). The human oral suspension is not recommended for use in pets.
The dose is 1 mg/kg twice daily. fexofenadine (Telfast®) – this is a second gen. It is available as 60 mg capsules and 120 or 180 mg tablets. The dose is 5–10 mg/kg once or twice daily (don't use if your dog is on ketoconazole or a macrolide antibiotic)
Telfast®- (active ingredient fexofenadine ) these are available in 60 to 180 mg tabs. But note that while not likely to overdose, the dosage for most dogs is only 5-10 mg / Kg once or twice a day.
Quercetin is a bioflavonoid that provides natural allergy relief for dogs reducing symptoms like itching, scratching, licking and chewing. Many veterinarians suggest quercetin because it is a safe, natural antihistamine for dogs. In fact, quercetin is often referred to as "Nature's Benadryl".
Apple cider vinegar has a lot of uses for not only humans but also pets. If your pet has itchy skin, this concoction of 50/50 water and ACV spray can help relieve your pet's skin allergies or irritation. This home remedy can also be used in a bath format.
Cetirizine (Zyrtec®, Reactine®) is an antihistamine used to treat and prevent pruritus (itching) associated with atopic dermatitis, urticaria (hives), and insect bite reactions in cats and dogs. Its use is in cats and dogs is 'off-label'. Many drugs are commonly prescribed for off-label use in veterinary medicine.
Oral antihistamines are another commonly prescribed medication for dogs diagnosed with a mild case of dermatitis. An antibiotic or antifungal medication might also be prescribed if a secondary infection is suspected. Yeast infections are also common. Immunotherapy is also another option available for dogs.
The main active ingredient in piriton is chlorpheniramine which is generally safe for dogs, but other brands may have cetirizine hydrochloride which isn't as safe for your pet.
Paracetamol is a very popular painkiller in humans, however it can be toxic or fatal in small animals. Dogs are less sensitive to paracetamol than cats. A 20kg dog would need to ingest over seven 500mg tablets in order to suffer toxic effects.
Should your vet prescribe paracetamol for your dog, it's likely that it will be a dosage of 10mg per kilogram, and should only be given once a day for one or two days.
Causes of Antihistamines Poisoning in Dogs
When a dog consumes antihistamines, depending on the amount ingested, toxicity can occur. Poisoning due to antihistamine overdose is caused by: The constriction of the smooth muscles in the respiratory tract. The increased permeability of the capillaries.
ANTI-histamines, such as diphenhydramine (Benadryl®), cetirizine (Zyrtec®), and hydroxyzine, are commonly taken by humans to treat allergy symptoms and can be used for dogs as well. These medications work by preventing histamine from binding to cells and exerting its effects.
You may be wondering whether Claritin or Zyrtec is the best pet allergy medicine—but which antihistamine works best for you depends on the severity of your symptoms. For example, a person with a mild allergy to cats or dogs may do well with Claritin. Another person with more severe allergies may do better with Zyrtec.
The active ingredient in Zyrtec is cetirizine. Cetirizine is an antihistamine commonly used to treat itchy skin in dogs. It's a popular prescription for canines because most dogs tolerate the medication very well, and it doesn't have the effect of leaving your pet sedated and lethargic.
Other safe antihistamines for dogs include Claritin (loratadine) and Zyrtec (cetirizine). They produce less sedation than Benadryl does but could still make your dog drowsy. Warning: Make sure your OTC allergy medicine only contains antihistamines.