More Information
Diphenhydramine is an antihistamine used to treat allergies, insect stings, motion sickness, travel anxiety and other conditions. It is available as 25mg and 50mg capsules . The usual dose in dogs and cats is 0.5-2mg/pound by mouth every 8 to 12 hours. This medication should not be used in pregnant or nursing animals.

Generic Name
Diphenhydramine (dye-fen-hy'-dra-meen)

Brand Name(s)
Benadryl (Warner Lambert), Histacalm (Virbac)

What is this medication used for
Diphenhydramine is an antihistamine used in the treatment of allergies, insect bites or stings and other causes of itching. It is also used for its sedative and antiemetic effects in the treatment of motion sickness and travel anxiety.

Availability
Diphenhydramine is available as a prescription strength capsule and injectable as well as elixir.

How this medicine should be used
Diphenhydramine is FDA approved for external use in dogs and cats. Diphenhydramine oral and injectable is not FDA approved for use in veterinary medicine; however, it is a commonly accepted practice to use this medication in dogs and cats. The usual dose in dogs and cats is 0.5-2mg/pound every 8-12 hours. The slow release capsule should not be mixed or dissolved in food. Do not use diphenhydramine in combination products also containing sinus or cold medicine.

What are the side effects
Side effects of diphenhydramine include drowsiness, dry mouth and urinary retention. Rarely, vomiting and diarrhea can occur.

What special precautions are there
Do not use this medication in animals that are allergic to it or other antihistamines. Do not use in animals with glaucoma, prostate disease, urinary obstruction, and high blood pressure. Do not use in pregnant or nursing animals. Use with caution when given with other CNS depressant drugs such as tranquilizers or barbiturates. Always tell your veterinarian and pharmacist what other medications your pet is taking.

What special precautions are there
This medication should not be used in animals allergic to chlorpheniramine or similar antihistamines. Do not use chlorpheniramine when it is in combination with other medications such as acetaminophen or caffeine such as found in various cold and sinus products. Do not use in pregnant or lactating animals. Do not use in patients with glaucoma, prostate disease or urinary obstruction, stomach or intestinal obstruction, high blood pressure or hyperthyroidism. Use caution when given with phenothiazines such as acepromazine and other central nervous system (CNS) depressant medications. Chlorpheniramine should not be used with monoamine oxidase inhibitors (MAOIs) such as selegiline and Preventic tick collar. Use caution when given with metoclopramide. Always tell your veterinarian and pharmacist what other medications your pet is taking.

Overdose - what to look for
To be supplied

Overdose - what to do
Contact Laguna Hills Animal Hospital (949-837-7333) or, if after hours, Animal Urgent Care (949-364-6228).

How should I store this medication
Keep this medication in the container it came in, tightly closed. Store this medication at room temperature, away from excess heat, light and moisture. Do not store in the bathroom. Throw away any medication that is outdated or no longer needed. Keep medication away from children and pets.