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.
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About Zyrtec for Cats
Zyrtec is an H1 receptor-blocking antihistamine. A chemical messenger called histamine causes the body to react by causing swelling, redness, and inflammation.
When allergens come into contact with the body internally or through the skin, histamine may be released. Histamine release causes the characteristic symptoms of allergies, such as runny nose and eyes. This is a typical response meant to aid in the removal of these foreign invaders from the body.
Interestingly, histamine isn’t only involved with the immune system. Additionally, it functions as a signal transmitter in the brain, spinal cord, and uterus and plays roles in the digestive system, particularly the stomach.
An antihistamine is a substance that works to inhibit the release of histamine, which stops the inflammatory reaction and the tearing and drainage that we all associate with allergies and generally detest.
Also Read: The 5 Best Medication For Cat Allergies
There are a couple of classes of antihistamines. First-generation antihistamines include diphenhydramine (Benadryl). This class of antihistamines can influence histamine’s function as a neurotransmitter by passing through the blood-brain barrier, particularly in relation to how it impacts the wake-sleep cycle. This is why Benadryl tends to cause sedation.
At appropriate dosages, antihistamines of the second and third generations do not elicit drowsiness or sedation because they lack this ability. They also tend to interact with fewer drugs.
There is also another class of antihistamines called H2 blockers. These have an effect on histamine, which is a component of the digestive system. Among them are medications such as famotidine, which inhibits the production of acid in the stomach.
Zyrtec is a second-generation antihistamine that is specific to H1 and only inhibits the histamine type linked to allergies. It usually doesn’t make you feel sleepy.
Also Read: The Meanings of the Eight Most Often Used Cat Sleeping Positions
How much Zyrtec can you give a cat?
The dose for over-the-counter Zyrtec (cetirizine) is 2. 5-5mg per cat given once to twice a day. When treating allergy symptoms like itchy skin, runny nose, or watery eyes, this dosage is usually safe to use. However, many other more serious conditions can appear like allergies. Make sure your cat gets examined by your veterinarian as soon as possible if the symptoms do not go better after one or two doses.
FAQ
How much Zyrtec should I give my cat?
Drug
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Dosage
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Cetirizine
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Dogs: 1 mg/kg or 10–20 mg per dog, PO, q 12–24 h as needed
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Cats: 1 mg/kg or 5 mg/cat, PO, q 12–24 h as needed
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Fexofenadine
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Dogs: 2–5 mg/kg, PO, q 12–24 h as needed
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Cats: 10–15 mg/cat, PO, q 12–24 h as needed
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Does Zyrtec work with cat allergies?
What antihistamine is safe for cats?
Is Zyrtec safe for pets?