Does Benadryl Make Dogs Sleepy? Benefits, Dosages, & Side Effects

benadryl dog

Benadryl is a widely known and well-used antihistamine in both human and veterinary medicine.

It has been used in veterinary medicine for various issues like allergies, anxiety, and even motion sickness.

But how safe is it really for our dogs and what are the effects on dogs?

Key Takeaways

  • Benadryl can be used to induce drowsiness in dogs, but should not replace a veterinary-prescribed sleep aid or anti-anxiety medication
  • Weight-based dosage guidelines should be followed and individual needs may vary when giving Benadryl to dogs
  • There are several alternative treatments such as medicated shampoos, supplements, prescriptions, medications, and comprehensive approaches to management available for canine allergies and anxiety management.

What are the effects of Benadryl on dogs?

The active ingredient in Benadryl is diphenhydramine which can cause drowsiness in dogs. This is not usually the primary reason for administering Benadryl to dogs but many pet owners find it beneficial in certain situations like during travel or fireworks.

However, owners should keep in mind that Benadryl is not intended as a primary sleep aid or anti-anxiety medication for dogs.

Benadryl works by inhibiting the receptors that receive histamines thereby alleviating many allergy-related symptoms such as an allergic reaction.

The antihistamine property can lead to sleepiness and result in drowsiness and light sedation in dogs.

However, the sleepiness effect varies depending on the individual dog, underlying health conditions, and the dose given.

How long does it take before my dog becomes drowsy?

The onset of sleepiness in dogs after administering Benadryl is typically immediate, which can be helpful for dogs experiencing seasonal allergies

How long does the sedative effect generally last?

The sedative effect generally lasts for eight to twelve hours in dogs.

What are some uses of Benadryl for Dogs?


The most common use of Benadryl for dogs is by far to manage allergies. It can help alleviate mild allergy symptoms short term in dogs, such as:

  • Hives
  • Swelling on the face or body
  • Red and itchy eyes
  • Itchy and inflamed skin
  • Signs of allergies like sneezing, coughing, or runny eyes

It can be helpful in treating mild allergic symptoms associated with allergies including those caused by pollen, mold, house mites, and common food allergens like chicken or beef.

However, if your dog has a more severe allergic reaction such as an anaphylactic reaction that can include difficulty breathing it may not be beneficial and it is crucial that you see a veterinarian immediately.

Also, Benadryl is meant for short-term use. If your dog suffers from allergies you should speak with your vet about long-term management with other medications like Cytopoint or Apoquel.

Managing anxiety

Aside from some immediate allergy relief, in some cases, the drowsiness induced by Benadryl can be advantageous. For instance during car travel, fireworks, or other stressful situations.

The calming effect of Benadryl can help your dog relax and better manage loud noises or unfamiliar environments but since this is not the primary recommended medication for such situations it is best to speak with your vet about using a more effective medication to address your dog’s anxiety.

While this is not a primary reason to give Benadryl, many dog owners reach for it during times of high stress.

However, in some cases, Benadryl has the potential to actually have the opposite effect and can increase anxiety in some dogs.

It is not typically recommended for treating anxiety in dogs and if your dog suffers from anxiety it is important to consider other options like calming supplements, veterinary prescribed medications, or training and behavior modification techniques.

Benadryl Dosage for Dogs

It is important to you to determine the proper dosage of Benadryl for your dog with a veterinarian however, the general guideline is to give 1mg per pound of body weight.

Weight-based guidelines are not one-size fits and you may need personalized dosage adjustments based on your dog’s unique needs and health condition.

When adjusting the dosage of Benadryl for your dog’s specific needs, it is crucial to consider factors such as their overall health, sensitivity to medication, and any underlying health conditions.

Certain medical conditions may necessitate an adjustment in the dosage of Benadryl including:

  • Glaucoma
  • COPD
  • Cardiovascular Disease
  • Prostate Disease
  • Hyperthyroidism

Potential Side Effects of Benadryl in Dogs

Benadryl is a medication and can have side effects if given to dogs and in some rare cases can lead to an overdose.

Common side-effects include

  • Dry mouth
  • Drowsiness
  • Urinary retention
  • Increased Heart Rate
  • Excitability
  • Upset stomach symptoms
  • Allergic reactions

Rare side effects can include seizures, disorientation, and coma. If your dog exhibits any unusual behavior or symptoms after taking Benadryl it is crucial to consult a veterinarian immediately.

Precautions When Using Benadryl For Dogs

Taking precautions when using Benadryl for dogs can help ensure their safety and well-being. By avoiding harmful ingredients you can minimize the risk of side effects.

Avoid harmful ingredients

If giving liquid Benadryl ensure that it does not contain harmful ingredients like xylitol, sodium, or alcohol before administering it to your dog. Xylitol is an artificial sweetener and can be highly toxic to dogs as it can potentially cause severe hypoglycemia and subsequent liver damage.

Some formulations of Benadryl can contain other substances like phenylephrine which can be detrimental to canine health as well.

Always check the label and consult with your veterinarian if you are unsure about a specific Benadryl product.

Consult a veterimnarin

As with any medication consulting a veterinarian before giving your dog Benadryl is crucial, especially if they are on other medications.

They can provide personalized advice based on your dog’s specific needs and health conditions.

This ensures the safe and effective use of Benadryl, minimizing the risk of side effects or adverse reactions.

Alternatives to Benadryl for Dogs

While Benadryl can be helpful in a clutch it is not always the most effective option.

Allergy treatments

For dogs with allergies alternative treatments such as medicated shampoos, supplements s or prescription medications like Apoquel may be more effective than Benadryl.

Some popular alternatives include Cytopoint and Apoquel which most veterinary clinics readily carry.

Also, supplements like Omega-3 fatty acids and probiotics may also help treat allergies in dogs.

Anxiety management

For dogs with anxiety, you do not want to give Benadryl long-term as it can begin to have the opposite of the desired effect and cause more excitability.

Anxiety management

For dogs with anxiety, other options may be more effective than Benadryl. Calming supplements, medications, training, and pheromones are all viable options for managing anxiety in dogs.

Some pet owners find their pets get some relief through natural options like

  • Melatonin
  • Chamomile
  • CBD

Frequently Asked Question

How quickly does Benadryl make dogs sleepy?

Benadryl usually takes about 30 minutes to take full effect, making it a suitable mild sedative for motion sickness or other situations where your dog may feel anxious.

How much Benadryl should I give my dog to make him sleepy?

A safe dosage of Benadryl for dogs is 1mg per pound of your dog’s body weight. For example, a 25-pound dog would receive 25 mg and a 75-pound dog would receive 75mg.

Will my dog sleep if I give him or her Benadryl?

Yes, Benadryl can make your dog sleepy due to its common side effects such as drowsiness.

What should I expect when I give my dog Benadryl?

Common side effects may include drowsiness, dry mouth, hypersalivation, increased heart rate, rapid breathing, and excitability.

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