Which antihistamines are safe for dogs?
According to the American Kennel Club (AKC), you can give the antihistamine Benadryl (diphenhydramine) to your dog, but you should always check with your vet first. Although the U.S. Food and Drug Administration has not approved Benadryl for dogs, it is safe in the appropriate dose, and it is commonly used by vets to treat skin allergies that cause itching and scratching.
Benadryl can be used to treat dogs with:
- Hives
- Swelling
- Cough
- Sneezing
- Runny eyes or nose
Because Benadryl has a side effect of drowsiness, it may also be given to calm an anxious dog or to prevent motion sickness if your dog needs to travel. Your vet may tell you to avoid Benadryl if your dog has certain medical conditions or your dog is or may be pregnant. Your vet may also want to see your dog to find out what is causing your dog’s symptoms.
Benadryl can be dangerous for your dog if you give too much. An overdose of Benadryl can cause seizures and other side effects. The safest way to give Benadryl is to give it according to the weight of your dog. AKC says the dose for Benadryl is 2 to 4 milligrams per kilogram of body weight, two to three times per day.
Do not use a time-release capsule form of Benadryl because it can deliver too much Benadryl to your dog.
Other antihistamines safe for dogs
Other antihistamines can also be given to dogs, based on their weight. These include the below antihistamines:
- Cetirizine
1 milligram per kilogram of body weight or 10 to 20 milligrams per dog, once or twice per day - Clemastine
0.1 milligrams per kilogram of body weight, two times per day - Chlorpheniramine
Dogs under 20 kilograms
4 milligrams, three times per day
Dogs over 20 kilograms
8 milligrams, three times per day
0.25 to 0.5 milligrams per kilogram of body weight, three times per day - Cyproheptadine
0.25 to 0.5 milligrams per kilogram of body weight, three times per day
1.1 milligrams per kilogram of body weight, two times per day - Fexofenadine
2 to 5 milligrams per kilogram of body weight, once or twice per day - Hydroxyzine
0.5 to 2 milligrams per kilogram of body weight, three to four times per day - Terfenadine
5 milligrams per kilogram of body weight, two times per day - Trimeprazine
1 milligram per kilogram of body weight, two times per day
The safest dose is different for different antihistamines, so always check with your vet first.
Related questions
References
- American Kennel Club (AKC). Benadryl for Dogs. April 2021. Available at: https://www.akc.org/expert-advice/health/benadryl-for-dogs/. [Accessed September 5, 2021].
- Merck Manual Veterinary Manual. Antihistamine Dosages. 2021. Available at: https://www.merckvetmanual.com/multimedia/table/v4695641. [Accessed September 5, 2021].
Read next
How long does Benadryl take to work?
Benadryl is quickly absorbed after oral administration and it starts to work within 30 minutes with peak effects reached within one to two hours. The effects of Benadryl last from four to six hours. Benadryl in the injectable form has a rapid onset of action. You will know when Benadryl starts to work because your allergy symptoms, such as congestion, runny nose, itchy eyes, or a skin rash, will start to feel better. Continue reading
Does Benadryl help with or cause anxiety?
One of the most common side effects with Benadryl is drowsiness, but in some people it can have the opposite effect, known as paradoxical excitation. Instead of feeling sleepy,
you may experience excitation, agitation or insomnia (trouble sleeping), which might make your anxiety symptoms feel worse. This may be more common in young children. Continue reading
Does Benadryl make you sleepy?
Benadryl (generic name: diphenhydramine) is an antihistamine that causes sleepiness in most people. Some people use Benadryl to help with sleep or insomnia, but this should only be for short-term use. Do not use Benadryl to make a child sleepy. Contact your doctor if you or your child are having trouble with sleep. Continue reading
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Drug information
- Benadryl Information for Consumers
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