Diphenhydramine Topical

What is diphenhydramine topical?

Diphenhydramine topical (brand name Benasoothe®) is an antihistamine with some local anesthetic properties. It is used to relieve itching and skin irritation in dogs, cats, and other animals.

The U.S. Food and Drug Administration (FDA) does not review non-drug health products (e.g., herbals, nutraceuticals, shampoos, and other supplements) for safety or effectiveness before they are sold to the public. Manufacturers of non-drug health products must ensure their products are safe and labeled accurately. 

The FDA requires that these non-pharmaceuticals contain a disclaimer that says, “This product is not intended to diagnose, treat, cure or prevent any disease.” Health Canada licenses “veterinary health products” after reviewing safety, efficacy, and manufacturing information provided by the manufacturer. These products are not tested by Health Canada.

"Your veterinarian is the best source of information 
about the safety of non-drug health products in pets."

Your veterinarian is the best source of information about the safety of non-drug health products in pets. Just because a product is natural does not mean it is safe. All medicines and medicinal plants are potentially toxic if used inappropriately or given at high doses. Supplements can also have side effects, like pharmaceuticals. Few supplements and herbs have been subjected to rigorous scientific trials to determine their efficacy. 

Although the information in this handout may be helpful, it also may be incomplete and may not represent the full range of effects the supplement could have on your pet.

How do I give my pet diphenhydramine topical?

Diphenhydramine topical comes in topical cream, gel, lotion, ointment, stick, shampoo, and spray forms. 

• All forms are applied topically directly to the skin. 
• Clean the affected area as directed by your veterinarian before applying the medication. 
• Wash your hands after application. Avoid contact with eyes.
• Do not allow pets to groom or lick the application site for at least 30 minutes after applying the medication.
• Give this medication to your pet for the entire time prescribed by your veterinarian, even if it appears that your pet is feeling better.

This medication will take effect quickly, in about 1 to 2 hours, but its effects may not be noticeable right away.

What if I miss giving my pet the medication?

If you miss an application, give it as soon as you remember. However, if it is almost time for the next scheduled application, skip the missed dose and resume the regular schedule. Do not give the pet two doses at once.

Are there any potential side effects from diphenhydramine topical?

Diphenhydramine topical may cause the following side effects:

• mild irritation at site of application

The following reactions are rare, but if they occur, contact your veterinarian immediately:

• an allergic reaction such as irregular breathing, rash, fever, puffiness and swelling around the face

Drug sensitivities can develop over time with repeated exposure. Your pet may have no reaction after the first few doses but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment.

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This short-acting medication should stop working within a few hours, though effects may be prolonged in pets with kidney or liver disease.

Are there any risk factors for this medication?

This medication should NOT BE USED in animals that:

• are allergic to any of the components
• have blisters, oozing wounds

This medication should be USED WITH CAUTION in animals that: 

• have a small body size
• need a large area treated

Are there any drug interactions I should be aware of?

Certain medications should be USED WITH CAUTION when given with diphenhydramine topical, including: 

• apomorphine

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.

Is any monitoring needed with this medication?

• Your veterinarian may schedule a follow-up visit after the course of medication is complete to ensure the condition has been cleared and/or do additional testing to ensure this is the right medication for the condition present. In this case, follow your veterinarian’s directions.
• At home, monitor for any abnormal changes. If these occur, discontinue the medication and contact your veterinarian.

How do I store diphenhydramine topical?

• Store the medication in its original container, protected from light, at room temperature.
• Keep the cap tightly closed.
• If your veterinarian or pharmacist has made a special (compounded) formulation for your pet, follow the storage recommendations and expiration date for the product.
• Keep medication out of reach of children and pets.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Adverse effects should also be reported to the FDA or Health Canada.