Benadryl for Dogs: Uses, Dosage, Side Effects

Benadryl for Dogs: Uses, Dosage, Side Effects

by Scritch

Benadryl is the brand name for a common antihistamine medication (diphenhydramine HCl) that is primarily used to treat allergies. Though Benadryl is not yet FDA-approved for veterinary use, it is generally considered safe for dogs and is often used for mild to moderate allergies. This medication is useful for your pet’s allergy symptoms like itching, hives, swelling and sneezing. However, it is also given to dogs and cats for bug bites and bee stings. Because it can cause drowsiness and may reduce nausea, some pet parents use Benadryl for anxiety or car sickness. 

Before giving Benadryl to your pet

If you are considering Benadryl as a treatment for your pet, there are a few important things to take into consideration.

  • Consult your vet: Though Benadryl is generally safe for dogs and cats, it’s always a good idea to first consult your vet before giving a new medication, especially if your pet has other health conditions or is currently on any medications. Benadryl should not be given to dogs with certain health conditions, like glaucoma, hyperthyroidism, and cardiovascular disease. 
  • Use the right kind of medication: Whether you use Benadryl or a generic brand, use medication whose only active ingredient is diphenhydramine HCl. Steer clear of combination cold and sinus medications. Choose the solid tablets rather than liquid gel caps which may contain alcohol (and may be more difficult to properly dose).
  • Give with food: One way to reduce potential side effects is to give this medication with food. For larger dogs (therefore larger doses) cutting the pill into smaller pieces can make it easier to disguise with food. 

Tip: After you get the green light from your veterinarian, it may come in handy to keep some Benadryl in your travel kit in case you need it on the go. 

Benadryl dosage for dogs

The general rule of thumb is 1 mg of Benadryl for every 1 pound of body weight. 

Tablets often come in 25 mg doses, but take note that they may also come in higher doses. Based on a 25 mg tablet, you can follow this general dosing guide:

  • ¼ tablet for extra small dogs up to 10 pounds
  • ½ tablet for small dogs 10-20 pounds
  • 1 tablet for medium dogs 20-30 pounds
  • 1 tablet for every 25 pounds of body weight for large dogs

Despite the dosage recommendations, if your dog has never taken Benadryl before, it may be wise to start off with half a dose and then wait a few hours in case of side effects or adverse reactions. 

Your dog can take Benadryl up to 2-3 times a day, or once every 8 hours, but it’s wise to chat with your vet about prolonged use. 

Side effects of Benadryl

The most common side effects of diphenhydramine HCl are drowsiness and mild disorientation. However, less common side effects can include vomiting, diarrhea, dry mouth, and urinary retention. If your dog experiences these side effects, give your vet a call.