5 Best OTC Allergy Medicine for Dogs

Ever wonder what is the best antihistamine for dogs with skin allergies? I have scoured the research and reviewed the data on over 10 different antihistamines in order to shine a light on the options that work best.

Best over the counter allergy medicine for dogs

What is the best allergy medicine for dogs?

Antihistamines are allergy medications that block the effects of histamine in the body. They’re commonly prescribed by veterinarians to treat symptoms associated with allergies such as watery eyes, runny nose, and itchiness.

  1. Benadryl
  2. Zyrtec
  3. Claritin
  4. ChlorTrimeton
  5. Tavist

While there are several different types of antihistamines available, most veterinarians recommend using Benadryl for dogs with skin allergies because it’s inexpensive, easy to administer, and well-tolerated by most pets.

Is Benadryl or Zyrtec better for dogs?

Benadryl and Zyrtec are two antihistamines that veterinarians often prescribe for dogs with allergies.

Benadryl is an older medication that is still available over the counter. It has been around for many years and has a good safety record. Benadryl works well for many dogs, but it does have some side effects, including drowsiness in some dogs.

Zyrtec is a newer antihistamine that was developed specifically for humans. It has fewer side effects than other antihistamines, and it’s generally well tolerated by most dogs.

As with all medicines, there are pros and cons to each option.

Benadryl can be given every 8 or 12 hours while Zyrtec can only be given once a day. Zyrtec also has a longer half-life than Benadryl so it stays in the bloodstream longer and therefore takes longer to kick in. So if you need fast relief, Benadryl may be the better choice.

Some dogs are hypersensitive to the antihistamines in Benadryl and may develop a severe reaction. If you suspect your dog has an allergy to Benadryl, consider trying Zyrtec instead.

Benadryl has been around longer, so it’s more familiar to vets and owners alike. Also, there are many different formulations — liquid, tablet, chewable tablet — so you should be able to find something that works best for your dog’s needs and situation.

Zyrtec is also available in several formulations: liquid, tablet, chewable tablet, and ointment (for skin). The ointment is often used as a spot-on treatment for skin allergies.

Benadryl and Zyrtec are both safe medications when used at recommended dosages and frequencies, but they do have some side effects that can be dangerous if they aren’t monitored closely by a veterinarian. Side effects include:

  • loss of appetite
  • vomiting
  • diarrhea
  • lethargy or sleepiness
  • restlessness or agitation
  • dry mouth
  • constipation or urinary retention (difficulty urinating)
  • excessive panting or drooling

What do vets prescribe for skin allergies?

The severity of the condition will determine how treatment will be approached. Here are some common medications that you can give a dog for severe skin allergies:


Antihistamines block histamine production and help relieve itching caused by allergic reactions. Most antihistamines come as tablets or liquids that must be given daily. Some of them are also available in topical form, which can be applied directly onto the coat to help relieve itching and scratching. Side effects may include vomiting, diarrhea and drowsiness so don’t give these medications without consulting your vet first if your dog has any other health problems such as kidney disease or heart disease (or if he’s an older dog).


These drugs reduce inflammation by preventing cells from releasing substances that cause it (histamine). They come in several forms and work best when given at the earliest signs of an allergic reaction. Corticosteroids aren’t safe for long-term use because they can cause side effects such as weakened immune systems, gastrointestinal bleeding, and behavioral changes. If your pet needs long-term treatment for allergies, talk to your vet about switching to another medication.

Immunomodulatory medications

Immunomodulatory medications, also known as immunosuppressive drugs or immune suppressants, are used to treat severe skin allergies in dogs when all other measures fail to provide relief from symptoms such as itching and scratching. These medications are typically used when other treatments have not worked or when they cause side effects such as lethargy or vomiting. They work by suppressing your dog’s immune system so that it cannot attack its own body tissues.

Conclusion of best antihistamine for dogs with allergies

When it comes to treating your dog’s allergies, there are many things you can do. From changing your dog’s diet to using natural remedies, the options are endless. However, one of the most effective ways to treat your dog’s allergies is by giving them an antihistamine.

It is important that you choose an antihistamine that is safe for dogs and will not harm them in any way. Here are some of the best antihistamines for dogs with skin allergies:

  1. Benadryl
  2. Zyrtec
  3. Claritin
  4. ChlorTrimeton
  5. Tavist



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Hannah Elizabeth is an English animal behavior author, having written for several online publications. With a degree in Animal Behaviour and over a decade of practical animal husbandry experience, Hannah's articles cover everything from pet care to wildlife conservation. When she isn't creating content for blog posts, Hannah enjoys long walks with her Rottweiler cross Senna, reading fantasy novels and breeding aquarium shrimp.

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