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Loratadine For Dogs (Uses, Dosage & Side Effects)

Loratadine is an antihistamine used to relieve allergy symptoms and is commercially available as Claritin®, Alavert®, and other brands. The veterinary form of loratadine does not exist on the market, but it can be prescribed for dogs to treat skin irritation caused by certain allergic reactions.

Although some drugs were originally created for human use, such as loratadine, it is a common practice for veterinarians to prescribe them to pets.

In the modern world, not only people face allergies, but also dogs. How many times has your dog been stung by a bee or had an allergic reaction to food? For such cases, as you will read below, loratadine may be prescribed by your veterinarian to relieve allergy symptoms.

In this article we will answer your questions about loratadine and dogs: whether loratadine is safe for dogs, the side effects, how much loratadine to give, Claritin versus Claritin-D, loratadine versus Benadryl, and much more.

What Is Loratadine?

Loratadine is a second-generation antihistamine for human use. It has no sedative effect and is prescribed for allergies, including allergic rhinitis and chronic idiopathic urticarial, and other skin allergies.

In case of food allergies, insect bites, or other allergies, your veterinarian may prescribe loratadine for your dog.

The route of administration is oral and can be purchased as pills or syrups.

Depending on the histamine receptors they block, antihistamines are of three types: 

  • H1
  • H2
  • H3 

Loratadine is an H1 antagonist and has the capacity to inhibit histamine release from human basophils (blood cells that increase in number in case of allergies).[1]

Loratadine for Dogs

When it comes to loratadine for dogs, here are the things to remember:

  • It is a safe drug for dogs
  • It is used for various types of allergies
  • The usual dose is 0.1- 0.55 mg/pound (0.25 – 1.1 mg/kg)
  • It can cause side effects and interact with other drugs
  • It is administered only on the recommendation of a veterinarian

Is Loratadine Safe for Dogs?

Loratadine is a safe drug that is recommended by vets for various types of allergies in dogs. Like any other drug, it can have side effects, so it is recommended to talk to your veterinarian before giving your dog loratadine. If you buy Claritin, make sure it is not Claritin-D because it contains another substance in the composition that can be fatal to your dog.

Loratadine is a safe medicine for dogs if given on the recommendations of a veterinarian.

This drug can be bought without a prescription (over-the-counter/OTC), but you should consult your veterinarian before giving your dog any medicine, even OTC ones.

This drug should be administered with caution in puppies, pregnant females, and those with certain medical conditions, such as liver problems or dry eyes.

Is Loratadine Safe for Dogs

Loratadine Side Effects for Dogs

Like any other drug, loratadine has side effects, but unlike other antihistamines, it has fewer.

Among the most common side effects are:

  • Dry mouth
  • Vomiting
  • Nasal congestion
  • Decreased tear production
  • Diarrhea or constipation

Loratadine decreases tear production (as seen in humans), so it is best to avoid using this medicine in dogs suffering from keratoconjunctivitis sicca (dry eye).

Loratadine overdose can lead to:

  • Drowsiness
  • Hyperactivity
  • Palpitations

In rare cases, loratadine and desloratadine (the major active metabolite of loratadine) have been linked to clinically apparent acute liver injury in humans. [2] Therefore, it is recommended to use loratadine with caution for dogs suffering from liver conditions.

Loratadine should not be used for dogs that are hypersensitive or allergic to this medication.

dog in animal hospital

Loratadine Interaction With Other Drugs

For skin allergies, it is best to take (or administer) antihistamines in combination with omega 3 fatty acids due to their synergy. 

Drug synergy is the interaction of two or more drugs that have similar mechanisms of action (how a drug or other substance produces an effect in the body) and whose therapeutic effect is equal to or greater than the added effects of each one of them taken separately.

For drugs that increase the loratadine plasma concentrations, it is not recommended to administer them together. These drugs are:

  • Erythromycin (antibiotic)
  • Cimetidine (stomach antacid)
  • Ketoconazole (antifungal)[3]

The most common clinical sign (side effect) seen with loratadine drug interactions is drowsiness. Co-administration of loratadine with ketoconazole or erythromycin may also put more “pressure” on the liver, as these drugs are metabolized in the liver.

dog on vet

Claritin versus Claritin-D

Caution should be taken when purchasing Claritin for your dog. Distinguish between Claritin and Claritin-D. Even though people can take both drugs safely, pets cannot take Claritin-D. An active substance in Claritin-D may cause the death of your pet.

The main active substance in Claritin is loratadine. Claritin-D contains loratadine and pseudoephedrine (240 mg), an active ingredient that effectively relieves nasal congestion.

Pseudoephedrine can be toxic to pets. 30 mg of pseudoephedrine for a 20-pound dog (~ 9 kg) may induce the following clinical signs:

  • Elevated body temperature
  • Nervousness
  • Increased heart rate
  • High blood pressure
  • Disorientation[4]

Ingestion of three 30 mg tablets can lead to convulsions and death.

If you accidentally give your dog Claritin-D or any other drug that contains pseudoephedrine, call your veterinarian as soon as possible.

Loratadine versus Benadryl

Both drugs are used to treat allergies in both humans and dogs. Compared to loratadine, Benadryl produces drowsiness at normal doses and it is also administered to treat insomnia in humans.

Benadryl (trade name) contains diphenhydramine as its active ingredient. Diphenhydramine is a first-class antihistamine H1 receptor antagonist, as is loratadine. The difference between the two drugs is that they are part of two different classes of antihistamines.

Benadryl is used to treat mild to moderate allergies in dogs. The instructions for administration are similar to those of loratadine. The difference is that Benadryl causes drowsiness and can be used when a dog needs something to make it a little sleepy, so it does not get impatient, bored, or barks when it needs to be calm and quiet.

As with Claritin-D, Benadryl is sometimes combined with other medicines. Read the leaflet carefully to make sure that the medicine you are giving does not contain other drugs besides diphenhydramine.

The usual dose of Benadryl in dogs is 2-4 mg/kg or 0.9-1.8 mg/pound, given 2-3 times a day depending on the severity.

Common side effects are:

  • Gastrointestinal disorders – vomiting and diarrhea
  • Dry mouth
  • Urinary retention

Benadryl should be avoided in dogs that are suffering from:

  • Low blood pressure
  • Cardiac conditions
  • Glaucoma
  • Pregnant females

General Guidelines For Using Loratadine In Dogs

Loratadine is an OTC antihistamine drug that is used to treat various types of allergies in dogs, such as insect bites, food, or vaccination allergies.

Histamines are chemicals that the immune system creates in response to an allergenic factor (food, insect saliva, vaccination, etc.). Antihistamines counteract the effect of histamines in the body.

Dogs can take loratadine for:

  • Insect bites – fleas, bees, wasps, spiders, or other insects that by stinging or biting create local or generalized reactions.
  • Bites from venomous reptiles.
  • Food allergies that cause itching, scratching, and redness of the skin.
  • Before vaccination, if the dog is known to be more sensitive to the vaccine.

Not all dogs are allergic to these triggering factors.

Loratadine Dosage For Dogs

The loratadine dose for dogs varies depending on the individual and the severity of its condition. Loratadine should not be administered unless the dog has been examined by a veterinarian first. Serious side effects or death may occur if you use drugs without the advice of your veterinarian.

Claritin contains 10 mg loratadine per tablet. The dosage for dogs is between 0.1- 0.55 mg/pound (0.25 – 1.1 mg/kg).

According to the Merck Veterinary Manual, the recommended dose of loratadine for dog allergies is 5-10 mg/animal once or twice per day, orally. For example, if you have a Chihuahua, you will be administering ¼ tablet 1-2 times a day, depending on its condition and severity. Loratadine can be administered with food.

If you forgot to give your dog one dose, do not double the next one. Give your dog its medicine when you remember and time the next one accordingly.


Loratadine is a human drug used to relieve allergy symptoms. It can also be administered for pets against allergies caused by bites from insects or venomous reptiles, food, or vaccinations.

Loratadine is safe for most dogs but should be administered with caution for puppies, pregnant females, and dogs with liver disease or dry eye (keratoconjunctivitis).

The interaction between loratadine and erythromycin, cimetidine, and ketoconazole should also be considered.

Be careful not to give your dog Claritin-D as pseudoephedrine can lead to the death of your pet.

If one of the following clinical signs occurs, discontinue use and contact your veterinarian: dry mouth, vomiting, diarrhea, constipation, and/or decreased tear production.

Loratadine overdose may lead to palpitations, drowsiness, or hyperactivity.

About Iulia Mihai (DVM)

Dr. Iulia is a certified veterinarian with more than 10 years of experience in the field. With extensive knowledge of diet, care, and medication, she helps Misfit Animals provide readers with accurate knowledge on technical topics.

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