Benadryl For Dogs: Side Effects, Dosage & Alternatives



Yes, even your pup gets seasonal allergies. Wouldn't Benadryl for dogs be great; because we all know how bothersome itchy skin and a runny nose can be. Some dogs have mild allergies, while others suffer from more severe allergies. Most of the time, it's food-related. After all, many dogs love to dive deep into a dirt pile or squirm around in the grass, most of the time without an itch or rash.


But there are some pups certainly allergic to grass, dirt, and certain foods. In fact, it's more common than you think! Before we get into it, let's talk about whether dogs can take Benadryl in the first place. If they can't, what are some alternatives? Keep reading to learn more!



What Is Benadryl For Dogs

Dog Benadryl is just what it sounds like. It is an antihistamine that'll relieve little Max or Lily's allergies! Antihistamines block the effects of histamines in the body. This happens both in your dog's system as well as your own. Histamine is released when your body or your dog's body detects something harmful, like an infection. 


Benadryl is the name brand for the active ingredient diphenhydramine HCl. While Benadryl is not FDA- and vet-approved, it is safe for dogs and cats. Diphenhydramine blocks receptors that receive histamines in the body. This may relieve allergy symptoms like itching, sneezing, and hives. The body produces histamines, but the receptor antagonist blocks receptors from interacting with the histamines. 


Here are a few things that Benadryl can treat in dogs. 


  • Hives
  • Swelling and inflammation
  • Redness
  • Runny nose and eyes
  • Coughing
  • Sneezing
  • Anaphylactic reaction 
  • Insect bites
  • Environmental allergies 


If and when your dog has a severe allergic reaction, it is important to immediately take them to an emergency veterinary hospital. Allergies may range from mild, moderate, and severe. We know that any signs of discomfort in your pet are hard to see, regardless of severity. We recommend calling a veterinary office and getting some advice as soon as symptoms of an allergic reaction occur. 



owner feeding medicine to dog



Dosage Of Benadryl For Dogs

Discuss what's the proper dosage for your dog should be discussed with an experienced veterinarian. According to the Merck Veterinary Manual, the recommended dose is 2-4 milligrams of Benadryl per kilogram of body weight, about two or three times a day. A simple and practical dose is 1 milligram of Benadryl per pound of your dog's weight. A 10-pound dog would receive a 10-milligram dose in the morning, afternoon, and evening. This dosage varies depending on the medical history of your dog. 


Never implement slow time-release capsules for dogs. Capsules absorb differently in a dog's body than in humans, and it may affect the precision of your dosing for your dog. They may also break open when chewed, causing too much medication to be delivered at once, putting your dog at risk of an overdose. Administer children's Benadryl once you ask your veterinarian for the correct dosage.


This medication is not intended for puppies as they may be sensitive to certain medications. It is also not recommended for pregnant or nursing dogs. 


How to Administer Benadryl to Your Dog

We all know from experience that taking medicine is not pleasant! Especially when it tastes like grape cough syrup! Yuck! As most of us know, Benadryl, along with other antihistamines, has no particular taste. Unfortunately, your dog may not know that. They do not necessarily smell like anything yummy to your dog, but it doesn't look pleasant to eat either! 


If you're lucky, your pup will consume the capsule as is. Though, that might be wishful thinking. Here's a pro tip: an easy way to get your pup to take their pills with no fuss is to hide it in their favorite food or alongside their favorite dog treat. Please do this by either crushing the pill into a powder or wrapping it in the food itself. Masking the smell taste of the pill in a treat or their food will make it invisible for most dogs. Your dog will be enjoying a treat and be allergy-free in no time.





Side Effects Of Benadryl For Dogs

How much Benadryl to give your dog is a big factor in the side effects of this medication, as well as the severity of those side effects. Benadryl tablets are safe for dogs and cats, but it is always important to know what you may be getting into if any adverse side effects occur. Most of these are mild and won't last very long. 


Here are a few symptoms you may want to look out for:


  • Drowsiness
  • Dry mouth
  • Urinary retention
  • Hypersalivation
  • Increased heart rate
  • Rapid breathing 


Rare side effects include:


  • Diarrhea
  • Vomiting
  • Decreased appetite
  • Increased appetite 


It is best to avoid liquid Benadryl for dogs because it is high in sodium. This can cause other side effects. Also, avoid any form of antihistamines that contain alcohol.



Cost Of Benadryl

The lowest price for the most common version of generic Benadryl is around $0.75. This is 86% off the average retail price of $5.68. There are different types of antihistamines available. Usually, they are found over the counter, and you can easily pick them up without a prescription. 


Your vet may recommend Diphenhydramine as an injection and can only be done so with a prescription. As mentioned above, it is available as the generic drug or the brand name Benadryl. It is a lot more costly to get it administered as an injection, as you will likely have to pay per unit as you would with any other medication. For example, 100 mg/mL will cost you $.83 per unit, which will roughly come out to about $83.


Interaction With Other Drugs

Antihistamines may interact with other drugs. While it is likely that your dog is on neither of these medications, it is always important to be aware of any possible chemical interactions. Here are a few drugs that may interact with Benadryl or other antihistamines!


  • Sleeping medications
  • Sedatives
  • Muscle relaxants
  • Antidepressants


These interactions stem from pairing an antihistamine (like Benadryl) with any other medication that induces drowsiness. Keep in mind that antihistamines for dogs are not to be consumed in pediatric or neonatal pets. Implement this drug cautiously in dogs with:


  • Glaucoma 
  • Prostate enlargement 
  • Intestinal or bladder obstruction
  • Elevated thyroid hormone
  • Heart disease
  • High blood pressure


Be sure to tell your veterinarian about any medications, including vitamins, supplements, or herbal therapies your dog may be taking. Your veterinarian will likely advise you to monitor your dog for any abnormal behavior or side effects. While Benadryl is generally well-tolerated among animals and widely consumed in veterinary practice, you never know how your pet may react. If you suspect a Benadryl overdose call your veterinary office immediately.



black dog eating medicine





Ingredients in Benadryl

Diphenhydramine is active ingredient in Benadryl. Benadryl is just the brand name for this antihistamine! Safe to say that the active ingredient in Benadryl is Diphenhydramine! 


Here are a few inactive ingredients.


  • Carnauba wax
  • Dibasic calcium phosphate
  • Croscarmellose sodium
  • Hypromellose
  • Magnesium stearate
  • Microcrystalline cellulose
  • Polyethylene glycol


We know this all sounds like science mumbo jumbo, but we can assure you that it's important! Dog's symptoms vary when it comes to allergies, and at times, what they are experiencing may not even be an allergic reaction. Always consult your vet about the appropriate dosage of Benadryl or any other antihistamines.



Benadryl Alternatives 

While nothing can effectively replace medication needed by your dog experiencing allergies, there are a few alternatives to Benadryl to try. While we recommend these as alternatives, it is always important to ask your vet if any of these are right for your dog before starting any regimen. 


Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is an antioxidant found naturally in onions, apples, and other produce. Research shows that Quercetin exhibits antihistamine properties. A study conducted in 2007 found that it lessened respiratory side effects of allergies in rats by reducing the inflammatory response in the airways. 



Now, for our final recommendation for allergy relief, CBD! CBD oil and CBD dog treats are generally well-tolerated among people and pets. 


As you already know or probably don't, CBD supports your dog's endocannabinoid system (ECS), which is a regulatory system present in all mammals responsible for many important functions in your and your dog's body, including sleep, appetite, digestion, and mood. CBD interacts with their CB1 and CB2 receptors to help your pup relax and relieve any discomfort or nervousness. Effects of CBD include:


  • Improve sleep
  • Boost mood
  • Soothe aches and discomfort
  • Improve appetite
  • Relax the mind and body


CBD does not suppress the immune system, but it may help by managing the allergy symptoms experienced by dogs. CBD is one of the best natural substances given to dogs. As mentioned previously, it comes in various forms, such as dog treats, soft chews, and tinctures. 


We want to remind you once more that while all these products mentioned above may work, it is always best to consult with your dog's vet to ensure that you are using what is best for their health! For more info on medications for dogs check out these resources. 


Read Next: Metacam For Dogs: Side Effects, Dosage & Alternatives


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