Updated on May 26, 2013
Benadryl is a safe and non-toxic antihistamine that can be used in veterinary practice for allergies, anxiety, bee stings and insect bites, travel and car sickness, ear infections, hives, hot spots, as a mild tranquilizer and sedative, and after shots. It can relieve itching, cold symptoms, runny nose and eyes, sneezing, coughing and other similar inconveniences in a dog and other pets.
How to give Benadryl to dogs safely? How much, how often, and for how long? Your vet will prescribe the proper dose, based on your pet’s weight, age, and health condition. The average dosage charts that you will find online are based solely on the body weight, and do not take the age and condition of the pet into consideration.
The average dose of Benadryl for dogs is: 1 mg per 1 lb of body weight. Sources also state the maximum limits that shouldn’t be exceeded:
- 10 mg for dogs weighing 30 lb and less;
- 25 mg for dogs between 30 lb and 50 lb;
- 50 mg for dogs weighing 50 lb and over.
The dosage is usually administered every 8 hours, until the symptoms disappear.
You have to be very careful with the dosage when giving Benadryl to small dogs, such as Yorkies, Chihuahua, Maltese, and puppies. The same stands true for cats and kittens.
Vets prescribe Benadryl in a pill, liquid, or cream form. The easiest way to give Benadryl orally is to hide it inside a tasty dog treat or inside Greenies Pill Pocket capsules (special caps for medication that come as chicken and beef flavored).
How Long Does It Take to Work?
Benadryl for dogs can take as little as half an hour to work. Sometimes it can take longer, and sometimes it works only with the second dosage. If this antihistamine is not working, consult with your vet. It may be that your pet has a condition that calls for a different type of treatment. Also, do not alter the dose without first consulting your vet.
Is Benadryl Safe for Dogs?
Is there any danger in giving Benadryl to dogs? Unlike many of the over-the-counter human drugs, the OTC Benadryl is not toxic for pets. In general, it is exceptionally safe for dogs and cats.
The most common side-effect of this medicine is drowsiness, which can be helpful for the suffering animal. Other temporary side effects include: constipation, diarrhea, incontinence or difficulty urinating, and vomiting. In rare cases, Benadryl can cause nausea, anxiety, insomnia, nasal congestion, chills or sweating, and skin rash. These should go away right after discontinuation. Benadryl can dehydrate the body, which can be an issue for dogs with kidney damage.
Benadryl may be contraindicated for pregnant animals and very young puppies. It may also be contraindicated for animals with glaucoma and thyroid disease, among other conditions. Benadryl is contraindicated with certain medications, for example CNS depressants like Phenobarbital that is used to treat seizures in dogs. If the two are used simultaneously, the dog may become very sleepy and the combination can be very dangerous.
Generic Benadryl for dogs may have different ingredients than the name brand. If your vet prescribed Benadryl, you should not use generics or different antihistamines like Hydroxyzine or Chlorpheniramine, Claritin, Zyrtec, etc. Benadryl (Diphenhydramine) has been studied and used the most in veterinary practice, compared to other antihistamines. All the side-effects and reactions are known and vets prescribe it safely.
It is hard to overdose on Benadryl with an animal or human, but it does happen in rare cases. The main signs of overdose are swollen limbs and difficulty breathing. A major overdose can even lead to death. In case of an overdose, the owner needs to induce vomiting in their pet and contact their veterinarian immediately.
Steroid Shots vs Benadryl for Dogs
Steroids are another common medicine to treat varied allergic reactions and inflammation in dogs. Steroid injections work by rapidly suppressing the immune system. These shots can save lives, but sometimes they lead to dreadful side-effects like paralysis, blindness, and even death. Steroid shots are so much more dangerous compared to antihistamines like Benadryl.
If your dog or cat just has a runny nose or mild allergy, do remember about the potential danger of steroids. Consider the safer options first – try to determine and eliminate the allergen and talk to your vet about Benadryl for dogs to relieve the symptoms.