If your dog suffers from allergies, you may have heard of loratadine as a possible treatment option. Loratadine is an antihistamine that can help reduce the symptoms of allergic reactions in dogs, such as itching, sneezing, and inflammation. 

But what is loratadine exactly, and how does it work for dogs? Is it safe and effective, and what are the possible side effects? How much loratadine should you give your dog, and how often? 

In this article, we will answer these questions and more, to help you decide if loratadine is right for your furry friend.

What is Loratadine and How Does It Work?

Loratadine is a drug that belongs to the class of antihistamines, which are substances that block the action of histamine in the body. Histamine is a chemical that the immune system produces when it detects a foreign substance, such as pollen, dust, or food. 

Histamine causes various effects, such as dilation of blood vessels, increased mucus production, and contraction of smooth muscles. These effects are responsible for the common signs of allergic reactions, such as runny nose, watery eyes, coughing, wheezing, and itching.

Loratadine works by binding to the histamine receptors in the cells and preventing histamine from attaching to them. This reduces the intensity and duration of the allergic response and relieves the discomfort caused by histamine. 

Loratadine is available in different forms, such as tablets, syrup, and oral disintegrating tablets. The most common brand name of loratadine is Claritin®, but there are also other brands and generic versions available.

Benefits of Loratadine for Dogs

Loratadine can be used to treat various types of allergies in dogs, such as insect bites, food allergies, or vaccination allergies. It can also be used to treat atopic dermatitis, which is a chronic skin condition that causes inflammation, itching, and hair loss. Loratadine can help reduce the frequency and severity of the flare-ups and improve the quality of life of dogs with atopic dermatitis.

Loratadine has some advantages over other antihistamines, such as diphenhydramine (Benadryl®) or chlorpheniramine (Chlor-Trimeton®). Loratadine is usually well tolerated by dogs and has fewer side effects than other antihistamines.

It does not cause drowsiness or sedation in most dogs, which makes it suitable for daytime use. It also has a longer duration of action than other antihistamines, which means that it can be given once or twice a day instead of every few hours.

Risks and Side Effects of Loratadine for Dogs

Loratadine is generally safe for dogs when given at the appropriate dose and under the supervision of a veterinarian. However, like any medication, it can also have some risks and side effects. Some of the possible side effects of loratadine for dogs are:

  • Dry mouth
  • Increased thirst
  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Lethargy
  • Headache
  • Nervousness
  • Hyperactivity
  • Heart palpitations

These side effects are usually mild and transient, but they can also be serious or life-threatening in some cases. If you notice any of these signs in your dog after giving loratadine, stop the medication immediately and contact your veterinarian.

Some dogs may also be allergic to loratadine itself or to any of its inactive ingredients. This can cause anaphylaxis, which is a severe allergic reaction that can be fatal if not treated promptly. Anaphylaxis can cause symptoms such as:

  • Difficulty breathing
  • Swelling of the face, lips, tongue, or throat
  • Hives
  • Itching
  • Drooling
  • Collapse
  • Seizures

If you suspect that your dog is having an anaphylactic reaction to loratadine, seek emergency veterinary care immediately.

Another risk of loratadine for dogs is overdose. Giving too much loratadine to your dog can cause toxicity and serious complications. Some of the signs of loratadine overdose in dogs are:

  • Agitation
  • Confusion
  • Tremors
  • Convulsions
  • Coma
  • Death

If you think that your dog has ingested more loratadine than recommended, call your veterinarian or a poison control center right away.

How to Give Loratadine to Your Dog: Dosage and Frequency

The dosage and frequency of loratadine for dogs depend on several factors, such as the weight, age, health condition, and severity of the allergy of your dog. You should always consult your veterinarian before giving loratadine to your dog and follow their instructions carefully. Never give your dog more loratadine than prescribed or for longer than advised.

The standard dosage of loratadine for dogs to relieve allergies is 0.12 mg/lb to 0.22 mg/lb (0.25 to 0.5 mg/kg) once or twice a day. For example, a 20 lb (9 kg) dachshund would require 4 mg of loratadine, but a German shepherd weighing 60 lb (27 kg) would require approximately 12 mg of loratadine.

Loratadine is available in 5 mg and 10 mg tablets, as well as in syrup and oral disintegrating tablets. Tablets are best to give to dogs, so round up or down the dosage to the nearest half tablet. For example, if the dosage works out to be 4 mg, give one 5 mg tablet. If the dosage is 12 mg, give two and a half 5 mg tablets (makes 12.5 mg).

You can give loratadine to your dog with or without food, but make sure they have access to fresh water at all times. You can also use a pill pocket or a treat to make the medication more palatable for your dog.

Tips and Precautions for Using Loratadine for Dogs

Before giving loratadine to your dog, there are some tips and precautions that you should keep in mind:

  • Always check the label of the loratadine product you buy and make sure that it only contains loratadine as the active ingredient. Some products combine loratadine with a decongestant (such as Claritin-D®) or other ingredients that can be harmful or toxic to dogs2.
  • Do not use loratadine syrup in cats, as it contains propylene glycol, which can cause Heinz body anemia in felines.
  • Do not use oral disintegrating loratadine tablets in dogs, as they may contain xylitol, which is a sweetener that is poisonous to dogs.
  • Do not give loratadine to pregnant or nursing dogs, as it can cross the placenta and the milk and affect the development and health of the puppies.
  • Do not give loratadine to dogs with liver or kidney disease, as it can worsen their condition or cause complications.
  • Do not give loratadine to dogs with glaucoma, high blood pressure, heart disease, or thyroid problems, as it can increase the intraocular pressure, blood pressure, heart rate, or thyroid hormone levels.
  • Do not give loratadine to dogs that are taking other medications, especially antifungal drugs (such as ketoconazole), antibiotics (such as erythromycin), antidepressants (such as fluoxetine), or sedatives (such as diazepam), as it can interact with them and cause adverse effects.
  • Do not give loratadine to dogs that are allergic to it or to any of its components.
  • Monitor your dog’s response to loratadine and report any changes in their behavior, appetite, urination, or stool to your veterinarian.
  • If your dog’s allergy symptoms do not improve or worsen after giving loratadine, contact your veterinarian for further advice.


Loratadine is a type of antihistamine that can help relieve the symptoms of allergies in dogs. It can be used to treat various types of allergies, such as insect bites, food allergies, or atopic dermatitis. 

It has some advantages over other antihistamines, such as fewer side effects, less drowsiness, and longer duration of action. However, it also has some risks and side effects, such as vomiting, diarrhea, nervousness, heart palpitations, or overdose. 

You should always consult your veterinarian before giving loratadine to your dog and follow their instructions carefully. You should also monitor your dog’s response to loratadine and report any changes in their condition to your veterinarian. 

Loratadine is not the only option for treating allergies in dogs. There are other alternatives that you can consider, such as corticosteroids, immunotherapy, omega-3 fatty acids, or natural remedies. You should discuss these options with your veterinarian and choose the best one for your dog’s needs.