Your veterinarian can prescribe diphenhydramine capsules for dogs. It's best to avoid using liquid Benadryl if it contains sodium, which can cause other side effects. Also, avoid any form of Benadryl that contains alcohol. Your vet can prescribe diphenhydramine liquid for dogs.
Antihistamines are usually safe but can make some dogs drowsy and others hyperactive. OTC antihistamine preparations may contain other ingredients such as decongestants that are not safe for dogs. Read the label carefully to ensure that the product only contains antihistamine.
There is no clear evidence that any one antihistamine works better than another, so other factors can be considered when choosing an allergy medication.
It is recommended to give your dog 0.5mg per pound of body weight. You can safely give Zyrtec to your dog up to 20 mg per day. It should only be administered orally.
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.
Fexofenadine is available over the counter but should not be administered unless under the supervision and guidance of a veterinarian. This drug is not approved for use in animals by the Food and Drug Administration but it is prescribed legally by veterinarians as an extra-label drug.
Here's the recommended Zyrtec dosage for dogs based on their weight: Less than 10 pounds: 2.5 milligrams (half of a 5-milligram pill or a quarter of a 10-milligram pill) 10–50 pounds: One 10-milligram tablet. 50+ pounds: Up to two 10-milligram tablets.
According to the Merck Veterinary Manual, the standard dose for Benadryl® is 2–4 milligrams per kilogram of body weight, or 0.9–1.8 milligrams (mg) of Benadryl® per pound. Therefore, a simple and practical dose is 1 mg of Benadryl® per pound of your dog's weight, given two to three times a day.
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.
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.
If an antihistamine has an additional active ingredient, like pseudoephedrine, your pet may experience severe hyperactivity, hallucinations and even seizures. Because it does not take much of this ingredient to become detrimental, exposures can be life-threatening.
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.
Apoquel is used to help dogs with their skin itching and inflammation caused by allergies. Apoquel is associated with more side effects than Zyrtec or CBD – some of them quite serious. Zyrtec and CBD alone or combined are likely safer for your dog if they successfully control your pet's itching and inflammation.
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.
However, you should never give your dog Claritin without first consulting your vet. Claritin is largely considered safe, but there's simply no reason you shouldn't check with your vet first. Also, it is important to avoid some forms of the medication, which may contain other drugs that are dangerous.
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Allergies in dogs are different than allergies in people. Histamines cause upper respiratory allergies in people, whereas cytokines (not histamines) cause itchy skin in dogs. For dogs with underlying allergies, antihistamines don't control the cytokines (signaling proteins) that cause inflammation and itch.
Diphenhydramine (Benadryl): 1mg per pound (one 25mg tablet for a 25lb dog) twice daily. Cetirizine (Zyrtec) ¼ - ½ mg per pound (one 10mg tab per 30-40 lbs) twice daily.
ZYRTEC 10 mg film-coated tablets
You can divide the tablet into two equal doses.
Cetirizine can be taken at any time of the day. In most people it is non-sedating, so they take it in the morning. However, a percentage of people do find it to be sedating so if it does make you drowsy it is best to take it in the evening. Cetirizine can be taken with or without food.