Benadryl for Dogs: Dosage, Benefits and Side Effects of the Drug


It is a common phenomenon among all the creatures in the earth to be affected by diseases and allergies of some type. Animals, like humans fall ill, feel irritated and need to heal either by the nature or thorough some external help. That being said, humans and animals react in a very different manner when it comes to medications.

The composition added to the medication of animals is quite different from that of humans. However, there are some medications that are made for humans but can be used for animals as well, unless and until they are not used inappropriately. Benadryl is one such example and works as a wonder medicine when it comes to effectiveness. Sometimes Benadryl spelled wrong – benedryl for dogs.

You might have noticed that your dog experiences a lot of problems from time to time such as itchiness, running eyes, scabbed skin, vomiting, diarrhea etc. Well, all of these symptoms come from exposure to an allergen. While there are some allergens that are common to every dog, like sugary substance, there are a few allergens that are not common but might be affecting your dog. Either way, Benadryl is an excellent drug. Let us find out why?

The main content of Benadryl is Diphenhydramine, which is the most common and active ingredient and is really safe and helpful medicine when taken in right proportions. The medication contents H 1 antagonist, which helps to prevent the uptake of histamine by receptors in the body.

It relieves inflammation, itchiness, running eyes and all the other above symptoms discussed earlier. When the body produces histamine, the receptors block the registering of histamines. Benadryl though beneficial up to some respect, it is not an FDA approved drug yet, but can be considered safe ‘if’ used correctly and with an approval from the veterinary doctor.

Benadryl for dogs in addition to Diphenhydramine might also contain some other ingredients. When buying it over the counter, it is very important to read its content, and it should be remembered that Benadryl is only the brand name of a specific allergy relieving drug. Its substitutes can be as effective but always consult the vet before deciding the dosage for dogs.

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1. Introduction

2. Quick Links to Our Picks

3. How Сan Benadryl be Beneficial for Your Dog?

4. What Can Benadryl Cure in Dogs?

5. How Does Long It Is Take to Start Working?

6. How Does Benadryl Work?

7. Benadryl Dosage for Your Pet

8. Common Side-Effects Associated to Benadryl

9. Over Dosage

10. How to Give Your Dog Benadryl Dosage?

11. Product Review: Benadryl Allergy Ultratab

12. Other Frequently Asked Questions Regarding Benadryl

13. Conclusion

How Can Benadryl be Beneficial for Your Dog?

As stated earlier Benadryl is very safe when used correctly, but it does have some risks, complications and side effects. It is blocks the receptors that receive histamines and thus indirectly relieve from the allergy. This does not mean that body will not produce histamines.

The body of the dog will still generate histamines but since the receptors are blocked, the allergic reactions will never happen. Thus, in a way, allergies makes the histamines ineffective in the dog’s body. The medication works perfectly for sedation and motion sickness, but a routine dosage of the medicine is not recommended.

If serious problems get noticed in your dog like cardiovascular disease, high blood pressure, glaucoma, Benadryl can be harmful. It is even seen in many cases that dogs react to slight allergic conditions and don’t actually needs any medication. Benadryl is an OTC allergy blocker.

However, with all these effects in place, Benadryl for puppies is strictly not recommended because they do not have a body that can readily digest the ingredients of the drug.

What Can Benadryl Cure in Dogs?

Observations and experiments have proven Benadryl to be highly effective in the cases of mild to moderate allergies. To summarize the cases of allergies that Benadryl can cure in dogs include seasonal allergies, environmental allergies, food allergies and allergies to venomous reactions and insect bites.

Benadryl helps skin allergies and relieves conditions like itching, hives, swelling, coughing, sneezing, runny nose and red eyes. Here is a summary of how Benadryl is useful in some specific cases:

Food allergy and use of Benadryl

If your dog is experiencing some type of food allergy and if you aren’t sure if it is causing any harm to your dog, then it is generally recommended to get him checked by a vet. If you are on an oppose to that, then dose for dog of the medicine in question might be the right choice.

Reactions of dogs due to vaccination

Dogs might react negatively when vaccinated. Giving your pet a dosage of Benadryl half an hour before the vaccination might help it to reduce stress as recommended by vets. A very nervous or anxious dog can be a danger at times.

Calming effect of Benadryl

Benadryl has a calming effect due to the presence of sedative ingredients. When exposed to loud sounds your dog might get anxious and disturbed at times. Well, this is a common phenomenon and humans also get affected by this in particular. Benadryl can be a life-saving drug in such a case. To be safe it is an obvious recommendation to take medical advice.

Reaction to Hives

Adverse allergic effects such as Hives can be noticed at times in your dog. They are generally round and itchy bumps. You can even notice that your pet is getting a swollen face from time to time and it is common due to an allergic reaction in canines.

Benadryl can be a very beneficial and effective in reducing such symptoms in dogs.

How Does Long It Is Take to Start Working?

The content of Diphenhydramine takes around 30 minutes to start working. If it is being used to treat animals from motion sickness or to diminish their anxiety level it is best recommended to administer the medication 30 minutes before the stressful period.

How Does Benadryl Work?

As mentioned earlier, the main content of Benadryl drug is Diphenhydramine, which is in simple words a receptor antagonist, it blocks the receptors that receive histamines in the body.

When attached to H 1 receptors which happen to be the primary source of allergic reaction induction, it relieves many such symptoms that are associated with allergies like itchiness, hives, scabbed skin, etc but when it gets contact to H2 receptors it causes a very different reaction with symptoms of the cardiovascular disease, high Blood pressure and acid secretion in the stomach.

Benadryl Dosage for Your Pet

The Proper dosage of the medication is very crucial. If less quantity of the medication is used, it might not affect your pet and giving proportionally high dosage can result in something very dangerous and even life-threatening.

The best way to determine the correct dosage is by consulting your veterinarian. A recommended dosage of two to four mg per kg of body weight for two to three times a day, however, it depends on your pet’s existing medical conditions.

Topical type of Benadryl like that in cream form contains 1% to 2% of Diphenhydramine. Topical Benadryl for dogs is available in the form of gel and spray as well. It can be applied 2 to 3 times a day depending upon the severity of the allergic reaction.

Although topical medicine is the easiest and friendliest way of giving medication to the dog, many dog owners fail to realize that even applying or spraying a lot of medicine can lead to fatal conditions. In fact, studies show that giving an extra topical treatment can be as dangerous as giving oral overdose to the pet. Also, please note that topical medication can sometimes cause sensitivity and irritation in the dog.

Another form of Benadryl available is in the form of liquid Benadryl for dogs. While no vet recommends giving liquid Benadryl to the pets, using the (human) children’s liquid formula on pets is perfectly safe.

This is due to the fact that liquid Benadryl solution has a high concentration of the medicine; but the solution made for children has just as much medicine content as needed by an adult dog. However, it goes without saying that this formula should never be used to treat puppies.

Finally, Benadryl is also available in the form of injectable medication. However, this should only be given to the dog by a professional animal doctor. This mode of medication is only favored when a dog has a severe case of allergy-like air passage blocking due to allergic reaction. It is the fastest mode of application and the most effective one but at the same time giving dogs Benadryl through this method is rarely required.

In case of a severe allergic condition like that of snake bite or infectious insect bite, the dosage can be doubled, though it is recommended to take doctor’s advice in prior.

Common Side-Effects Associated to Benadryl

Just as a human body, dogs also react very differently when this medication is used. Food allergies, seasonal allergies, environmental allergies all might respond to the dosage of Benadryl in most cases, but they might also look a bit spaced out with these symptoms.

  • Sleepiness
  • Urinary retention
  • Dry mouth
  • Increased Heart rate
  • Diarrhea
  • Loss of Appetite
  • Vomiting tendency
  • Allergic reaction
  • Hypersalivation
  • Increased Heart rate
  • Prostatic Hypertrophy
  • Allergic Lung disease
  • Rapid breathing

Most of all these side effects occur within an hour of the medication. In severe cases, immediate veterinary care is a must recommendation. Apart from these common reactions, there are a few cautions that you must take before giving this medicine to the dog.

  • If your dog is already on a medication, Benadryl might not be the best solution to the allergies. It reduces the effectiveness of other drugs and can even react with other drugs and cause problems to the dog. Thus, always consult the vet.
  • Benadryl is not formulated to cure the allergy. It is just an alternative and quick solution to the problems caused by allergies. Therefore, it just works on the symptoms and reduces them but does not treat the actual disease. Thus, Benadryl, in dogs relieves the symptoms but your dog still needs to undergo other medications to cure the disease.
  • Since the composition of Benadryl is not the same throughout the world, you need to be extra cautious while feeding Benadryl to your dog. Always read the ingredients and consult a vet.

Over Dosage

Knowing the right Benadryl dose for dogs is a must. Though Diphenhydramine can be safe for treating allergies, anxiety, and a variety of other conditions but an overdosage of this medication can be harmful in most cases. It is seen that a normal dog can survive up to 16 times more than the recommended dosage if hospitalized, so it is likely to recover if acted fast.

Symptoms of overdosage include a very irregular heartbeat, breathing difficulties, fatigue, high blood pressure, hypersalivation, rapid breathing and even disorientation among other signs. The most common way to treat this is to make your pet vomit or use active charcoal. If your pet is suspected of getting an overdose of the Benadryl medication, call for immediate veterinary help.

How to Give Your Dog Benadryl Dosage?

Now after knowing all the factors related to Benadryl, you have opted for Benadryl dosage for your pet, here are few other tips which you should remember:

  • Weight your dog to make sure that you not under dose or overdose it.
  • Once done remember the dosage for Benadryl is 1mg/1lb of body weight in dogs. As stated earlier sometimes dosage can be increased in the case of severe allergic conditions. Consult your vet before doing it.
  • To avoid uncertain circumstances, make the tablet invisible by hiding it in the dog’s food, your pet can swallow it without even getting noticed.

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Other Frequently Asked Questions Regarding Benadryl

1. Can we give dogs Benadryl? Is it recommended and safe?

Generally speaking, the medication is considered relatively safe with a slight amount of side effects when taken in right quantity. It should be kept in notice while buying the medication over the counter to read thoroughly over the table of contents and Benadryl is just the brand name for Diphenhydramine.

2. How often can I give my dog Benadryl?

A dosage of 1-2mg / 1lb body weight is a general recommendation for dogs and its intake can occur 8 to 12 hours or every 2 to 3 times a day.

3. How does long Benadryl take to work?

Benadryl starts working within two to three hours from the time of consumption and its effect lasts till four to six hours after consumption. In stressed out situation Benadryl dosage can be given 30 minutes prior to calm their nerves.

4. When to avoid Benadryl dosage on dogs?

If your pet is under any other medications, then it is a recommendation to talk to the vet before giving Benadryl. Adult Benadryl formula contains alcohol which can be harmful at times.

5. Can I give my puppy Benadryl dosage?

Yes, according to veterinarians it is safe to provide puppies with Benadryl but in very limited quantity. The dosage for pups is same as that of dogs. However, like in the case of human babies, it should be remembered that their bodies are less developed and professional advice should be taken before the intake of the medicine.

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Well after discussing all the effects and side effects of the medicine, I can say it is absolutely safe to use it for your furry friend, but at the same time it is my recommendation to stick to the right dosage and seek for help in case of medical emergencies or unusual behavior.

If you’re interested in reading similar articles, here’s good one on Hydroxyzine for Dogs. We’ve also posted a good guide Best Probiotics for Dogs.