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. There are four types of 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.
- Allergic skin disease
- Urticaria (rashes)
- Insect bites and stings
- Blood transfusion reactions
- Vaccination reactions (administered prior to the vaccination)
- Mast cell tumours
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.
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 which are both toxic to cats.
Give 5 mg once a day, or as directed by your veterinarian.
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 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:
- Facial swelling
- Difficulty breathing
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.
Before giving loratadine, make sure that your cat is not taking other antihistamines or medications like cimetidine, 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.
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.