Claritin (Loratadine) For Cats

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  • At a glance

    • Drug Name: Loratadine
    • Common names: Claratin, Alavert
    • Drug Type: Second-generation antihistamine
    • Used For: Allergies, blood and vaccination reactions, urticaria, insect bites and stings
    • Species: Humans, cats, dogs
    • Administered: Tablet

    Loratadine (sold under the brand name Claritin among others) is a second-generation antihistamine used to treat allergy-related symptoms in cats. Second-generation antihistamines relieve symptoms of allergies without the drowsiness associated with first-generation antihistamines such as Benadryl.


    Antihistamines work by blocking the effects of histamine on certain cells within the body. When a cat has an allergic response, mast cells and basophils release histamine which binds to cells containing H1 receptors.

    Types of histamine receptors:

    H1 – Located in the smooth muscles, lining of blood vessels and airways.
    H2 – Found in the stomach cells and stimulates the secretion of stomach acid.
    H3 – Located in the neurons of the brain, influences neurotransmission.
    H4 – Found in the bone marrow and white blood cells, responsible for immune response.

    Common allergies in cats include flea allergies, food, dust and storage mites.



    Loratadine is available in 5 and 10 mg tablets and syrup. Do not give the syrup as it contains propylene glycol or Claritin-D which contains a decongestant that are both toxic to cats.

    5 mg once a day, or as directed by your veterinarian.

    Never administer medications unless prescribed by a veterinarian. Even over the counter medications are not safe without the approval of your veterinarian who knows your cat’s individual cats and medical history.

    What happens if I miss a dose?

    Administer as soon as possible; however, if it is close to the time for your cat’s next dose, do not administer, wait until the scheduled time. Never exceed the total stated dose.

    If your cat does accidentally receive a double dose, contact your veterinarian for advice.

    Side effects

    Side effects are rare with this medication but may include hyperactivity, depression and tachycardia (elevated heart rate), dry eyes, dry mouth, vomiting, and diarrhea.

    Consult your veterinarian immediately if your cat experiences any of the following symptoms:

    Overdose/acute toxicity

    Mild overdoses are generally not serious, but moderate to severe overdoses can cause heart and central nervous system effects [1]. If you suspect your cat has had too much Loratidine, seek veterinary attention immediately.


    The safe use of loratadine has not been established with pregnant or lactating cats.

    Do not give to cats with a known allergy to the drug.

    Loratadine can exacerbate dry eye by reducing the aqueous phase of the tear film.

    It may be necessary to adjust the dose for cats with liver or kidney disease.

    Loratadine will interfere with allergy skin test results. Always notify your veterinarian of medications (prescribed or non-prescribed) before the skin tests to ensure accurate results.

    Drug interactions

    Before giving loratadine, make sure that your cat is not taking other antihistamines or medications like cimetidine, macrolide antibiotics (erythromycin), or ketoconazole, which may interact with loratadine.


    The length of time your cat is on loratadine depends on the condition treated and how the cat responds to the medication. Always follow your veterinarian’s instructions.

    Antihistamine trials

    Your veterinarian may recommend a trial to determine the most effective antihistamine for your cat. Initially, your cat may need cortisone and antihistamines. Antihistamines don’t cure allergies; however, the side effects are less severe than those of cortisone. Not all antihistamines will work with your cat or will produce undesirable side effects, so a trial will help to determine the best type for your cat.

    An antihistamine is administered to your cat for ten days, and his response is monitored. If there is no improvement, he moves on to the next time of antihistamine until a suitable one is found.


    Store at room temperature, and protect from light and humidity. Keep human and pet medication in separate containers to avoid mixing medications and accidental administration of the wrong medication.


    Donald C. Plumb. Plumb’s Veterinary Drug Handbook 9th Edition. Page 983.


    • Julia Wilson, 'Cat World' Founder

      Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio