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Antihistamines

A representation of Antihistamines

Antihistamines are medications that help reduce allergy symptoms by blocking the action of histamines. Histamines are chemicals that your dog's immune system releases when it reacts to an allergen. Various factors, such as environmental allergens (pollen, dust mites, mold spores) or food allergens, can trigger allergies in dogs. There are many antihistamines that are suitable for dogs, both over-the-counter and prescription.

When should you use antihistamines?

Antihistamines can be used to help your dog with various allergy symptoms, such as:

Antihistamines can also have a calming effect and can therefore be used to relieve anxiety or prevent motion sickness if your dog has to travel.

Can dogs take antihistamines?

Yes, dogs can take antihistamines, but you should always check with your veterinarian first. Although the U.S. Food and Drug Administration (FDA) has not approved antihistamines for dogs, they are safe in the right doses and are often used by veterinarians to treat skin allergies that cause itching and scratching.

Your vet can tell you which antihistamine is best for your dog and how often you should give it. Your vet can also tell you if you should avoid antihistamines if your dog has certain medical conditions or if your dog is or may be pregnant. Your vet can also examine your dog to find out what is causing their symptoms.

Antihistamines can be dangerous for your dog if you give too much. An overdose of antihistamines can cause seizures and other side effects. The safest way to give antihistamines is to dose according to your dog's weight.

What types of antihistamines are there?

There are two generations of antihistamines:

  • First generation: these were the first to be approved by the FDA and have been used in the US since the 1930s. They act on histamine receptors in the brain, spinal cord and other receptors. A notable feature of this generation of antihistamines is their ability to cross the blood-brain barrier, resulting in drowsiness.
  • Second generation: These were approved by the FDA in the 1980s and have fewer side effects than the first generation. They mainly act on histamine receptors in the periphery and do not cross the blood-brain barrier as easily.

Here are some of the most commonly used antihistamines to treat allergies in dogs:

First generationSecond generation
Diphenhydramine (Benadryl, Sentry, PetArmor)Cetirizine (Zyrtec)
Hydroxyzine (Atarax, Vistaril)Loratadine (Claritin, Alavert)
Chlorpheniramine (Chlor-Trimeton)Fexofenadine (Allegra)

Which generation of antihistamines is better for dogs?

There is no clear answer as to which generation of antihistamines is better for dogs. It depends on various factors, such as:

  • The severity of the allergy symptoms
  • The reason for using antihistamines
  • The dog's individual reaction to the medication
  • The possible interactions with other medications or supplements

In general, first-generation antihistamines can be more effective at reducing itching and scratching, but they can also cause more drowsiness. Second-generation antihistamines may cause less drowsiness, but they may also be less effective at reducing itching and scratching.

What are the benefits of antihistamines for dogs?

Antihistamines can offer your dog some benefits, such as:

  • Relieving allergy symptoms that are causing your dog discomfort
  • Reducing inflammation and skin irritation caused by allergies
  • Improving your dog's quality of life and well-being
  • Preventing complications that can arise from excessive scratching or licking, such as skin infections or hot spots
  • Reducing anxiety or motion sickness if your dog is stressed or nervous

What are the side effects of antihistamines for dogs?

Antihistamines are generally safe for dogs when given in the correct dose, but they can also have some side effects, such as

Side effects may vary depending on the antihistamine used and the individual dog. If you notice your dog showing unusual symptoms or behaving differently after you have given them an antihistamine, you should contact your vet immediately.

How do you choose the best antihistamine for your dog?

There is no universal antihistamine that is best for every dog. Choosing the best antihistamine for your dog depends on several factors, such as

  • The type of allergy your dog has
  • The severity of the allergy symptoms your dog is experiencing
  • Your dog's individual reaction to the medication
  • The availability and price of the medication

The best way to choose the best antihistamine for your dog is to talk to your vet. Your vet will be able to give you a recommendation based on a thorough examination of your dog and their medical history. Your vet can also tell you how to dose and use the antihistamine correctly and how to monitor for possible side effects.

Are there natural alternatives to antihistamines for dogs?

Yes, there are some natural alternatives to antihistamines for dogs that can help relieve or prevent allergy symptoms. However, these are not as well researched or tested as the synthetic antihistamines and may also have side effects or interactions. You should always speak to your vet before giving your dog anything new.

Some natural alternatives to antihistamines for dogs are:

  • Quercetin: A bioflavonoid found in fruits and vegetables, quercetin has antioxidant and anti-inflammatory properties. It can help reduce the release of histamines and modulate the immune response.
  • Omega-3 fatty acids: Found in fish oil, omega-3 fatty acids can help reduce inflammation and support skin health. They can also relieve itching and make the coat shiny.

The authors assume that a veterinarian should be consulted if an animal is ill and that medication should only be taken after consultation with a doctor or pharmacist. Only an individual examination can lead to a diagnosis and treatment decision.

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