Cetirizine Hydrochloride for Dogs

Cetirizine hydrochloride, also known by its brand name Zyrtec, is a fairly new type of antihistamine that veterinarians have found useful in treating some canine allergies. Let’s look at what cetirizine does, what its common side effects may be and in what instances its use is not recommended.

How Cetirizine Helps Relieve Canine Allergy Symptoms

As an antihistamine, cetirizine relieves allergy symptoms that are caused by overproduction of histamine, a chemical your dog’s immune system produces in response to an allergen, which is anything that triggers an allergic reaction in your pet. Common canine allergens include dust mites, flea saliva and food ingredients.

Common canine allergy symptoms include:

  • face rubbing
  • itching
  • skin irritation
  • swelling
  • paw or leg chewing

If initial symptoms are left untreated, secondary problems such as hair loss or skin infections can develop. In severe cases of allergic reaction, your dog can develop hives or he may go into anaphylactic shock, which is a life-threatening condition that requires immediate medical attention.

Cetirizine is especially effective at relieving a dog’s canine atopic dermatitis or CAD. CAD is a condition in which your dog’s inhaled allergy shows symptoms on his skin. Dogs with CAD usually show symptoms when they are between 1 and 3 years of age.

Symptoms of CAD include

  • biting
  • chewing at the feet
  • hair loss
  • head shaking
  • irritated skin
  • licking
  • rubbing the muzzle
  • scratching the armpits or groin
  • thickened skin

Although any dog can develop CAD, there seems to be a genetic component to the condition. This means that some breeds are more prone to developing the condition than others. CAD-prone breeds include

  • bulldogs
  • Dalmatians
  • golden retrievers
  • Irish setters
  • lhasa apsos
  • Old English sheepdogs
  • terriers

How to Give Your Dog Cetirizine

Cetirizine is commonly administered as a once-daily tablet that your dog takes with or without food. The exact dosage will depend on your dog’s weight, and the length of time he takes it will depend on the severity of his symptoms.

Do not attempt to administer this medication to your dog without discussing it with your veterinarian. Also, make sure to give your dog medications that only contain cetirizine; decongestant formulas of the medication contain ingredients that could harm your dog’s health.

Cetirizine is considered a second generation antihistamine by veterinarians and physicians because it and other newer anthistamines are less likely to cause sleepiness in pets or people than the first generation antihistamines, which are well-recognized for their sedative effects.

Common Canine Side Effects of Cetirizine

Despite cetirizine’s second generation status, the most commonly reported side effect of cetirizine is drowsiness, which usually goes away as your dog’s body adjusts to the daily dose of medication.

Other common side effects may include:

  • constipation
  • excessive salivation
  • excitability
  • urinary retention
  • vomiting

If your dog begins vomiting, stop giving him the medication and contact your veterinarian’s office for additional instructions and the recommendation for a different type of antihistamine to treat his allergy symptoms.

When Cetirizine Should Not Be Given to an Allergic Dog

Ceterizine is considered safe for most dogs to take, but dogs with kidney problems should not take it because of the possibility of the medication causing urine retention and creating further complications with the pre-existing condition.