Can I Give My Dog Benadryl For a Road Trip?

Updated: 7/21/2021

Vacations are always more fun when you can bring your furry furiend along! Taking a road trip with your dog can be an exciting adventure, but it can also come with its own challenges. While there are many dogs who love sticking their head out the window and exploring new places, some pets can suffer from travel anxiety or motion sickness, which can make the trip stressful for your best pal.

Whether you are running cross country with your dog, RV camping, or just checking out a local attraction, you'll want to make sure your pooch can have as much fun as possible. Benadryl is a common, over-the-counter antihistamine for humans that can also be given to dogs to treat several kinds of issues. While widely known for its ability to treat symptoms of allergies and allergic reactions, Benadryl can also be beneficial in calming your dog’s anxiousness and motion sickness too. Once your pooch is free from fear and nausea, they can join in the fun! But how does Benadryl do all of this?

Diphenhydramine HCL is the active ingredient in Benadryl that treats common allergy symptoms such as itchiness, watery eyes and sneezing. When harmless substances such as pollen or certain foods enter the body, sometimes the immune system sees them as dangerous invaders and will produce histamines. These histamines carry messages throughout the body to trigger a fight against the invaders, which leads to the symptoms of an allergic reaction.

The antihistamine diphenhydramine blocks the histamines from binding to their receptor sites by taking their place, thereby stopping histamines from conveying their messages, which in turn stops the allergic reaction from occurring. The same receptors that bind to histamines are also associated with motion sickness, which is why diphenhydramine can also be used to reduce nausea when traveling in a car, boat or plane.

And while some humans may not like diphenhydramine’s sedative side effect, for dogs experiencing travel anxiety, the drowsiness can help keep them calm and relaxed along the trip.

While many veterinarians recommend giving Benadryl to dogs to help with these issues, there are several things you need to consider before you give this medication to your pooch.

While Benadryl is safe and can be beneficial for many dogs, there are some cases where you shouldn’t administer it.

First of all, you should always discuss your dog’s condition with your veterinarian before giving Benadryl to your dog. Many symptoms that are common to allergies can also be indicative of a more serious condition which could be worsened by taking Benadryl. Some dogs have pre-existing conditions that should be considered as well, such as glaucoma, seizure disorders, COPD, hypertension, hyperthyroidism, an obstruction in the bladder or digestive system, or heart failure. You should also use caution if your dog is pregnant or nursing, or is elderly.

You’ll also want to discuss any other medications your dog may currently be taking, as antihistamines can alter the effects of some drugs. Be especially cautious if your dog is taking sedatives, pain medications, anticholinergic medications, tricyclic antidepressants, warfarin, or glucocorticoids. Your veterinarian may alter dosages of Benadryl and other medications for your dog’s safety.

And of course, you should never give Benadryl to your dog if they’ve had an allergic reaction to it, or any other antihistamines in the past.

While you won't find Benadryl for dogs in your local pharmacy, it does come in several forms for human adults and children, including tablets, capsules, and liquid forms. When traveling, it may be easiest to pack tablets or capsules. Your veterinarian will also be able to help you choose what form is best for your dog. Children’s formulations may be better for dosing small dogs. If you are looking to use the liquid form, however, be aware that some may contain xylitol which is deadly to dogs, so be sure to read all of the ingredients before you administer it. And never use time-release capsules, as they absorb differently in dogs which can affect the dosage levels.

While a general dosing guideline is 2 to 4 mg per kilogram of your dog’s weight, given two to three times daily, your veterinarian may suggest a different dosage based on your dog’s existing medical issues or concurrent drug therapies. If you are using Benadryl to help your dog’s motion sickness, be sure to give it 30 to 60 minutes before you start the trip to keep your pup’s tail wagging. This medication can also be given with or without food.  

Benadryl works quickly, and you should start to see its effects within the first hour. Drowsiness is common, and is the key to treating your pup’s travel anxiety. Another side effect is dry mouth, so be sure water is available for your dog. Decreased urination, and an increase or lack of appetite can also occur.

In rare cases, side effects can be more severe and may indicate an overdose. If you notice agitation, hyperactivity, dilated pupils, vomiting, diarrhea, constipation, a rapid heart rate, or even seizures, seek emergency veterinary attention immediately. On a road trip, you may be unfamiliar with the area, or far from medical help, so it may be a good idea to administer Benadryl to your pup before the trip to test out their reaction to it.

Some dogs can also be allergic to Benadryl. While allergy symptoms can mimic the symptoms Benadryl commonly treats, you’ll be looking for worsening symptoms or allergy symptoms in a dog who does not suffer from environmental or food allergies. In these cases, stop administering Benadryl and keep an eye on your dog! This medication should discontinue working within 24 hours of administration, although some medical conditions can lengthen these effects.

When planning a trip with your dog, be sure to keep their specific needs in mind to make the time fun for them too. Having a dog first-aid kit is a great way to be prepared for anything that may occur. Be sure to include Benadryl in the kit for a safe and effective remedy for allergies, allergic reactions from things like bee stings, to help keep your dog relaxed and free from anxiety, and to make sure that motion sickness doesn’t ruin the adventure. No one wants to drive in a smelly car!

With the right precautions, and a passion for adventure, you and your dog will have a furbulous time!

Before you travel, get pet insurance for your dog to prevent high vet care costs. Anything can happen out on the road, and it's best to be protected just in case. Start comparing insurance plans from leading insurers like Healthy Paws and Embrace and save over $270 a year.