Diphenhydramine is an antihistamine used for the treatment of allergic reactions.


Diphenhydramine Basics
Diphenhydramine is available over the counter. No prescription is required. Diphenhydramine is an antihistamine. Diphenhydramine is used to treat allergic reactions, atopic dermatitis, or itchy skin, motion sickness, vomiting, coughing, or anxiety. Histamines are chemicals that are released in the body in response to inflammation or allergies. When histamines attach to H-1 receptors in the body, it causes the blood vessels to widen which leads to swelling and itchiness. Diphenhydramine blocks the effects of histamines, reducing inflammation and itchiness.

Diphenhydramine Warnings
Keep out of the reach of children and pets. Do not use in pets with known hypersensitivity to diphenhydramine. Do not use in pregnant or lactating animals. Use with caution in working dogs, as diphenhydramine can cause sedation. Use caution in animals suffering from lung disease, glaucoma, enlarged prostate, hyperthyroidism, heart failure, high blood pressure, gastrointestinal obstruction, or urinary tract obstruction. Diphenhydramine may interact with some other medications. Consult your veterinarian if your pet is also taking barbiturates, epinephrine, heparin, or tranquilizers. Diphenhydramine may cause excessive drooling, especially in cats. Store at room temperature. Store protected from light and moisture.

Diphenhydramine Directions
Use as directed by your veterinarian. Follow the instructions on the product label. Store diphenhydramine at room temperature. Diphenhydramine can be given with food.

Diphenhydramine Dosage FAQs
In the case of a missed dose of diphenhydramine, give it as soon as you remember or wait until it is time to give the next dose. DO NOT GIVE A DOUBLE DOSE OF DIPHENHYDRAMINE. In the case of an overdose of diphenhydramine, seek attention from your veterinarian. The following symptoms could be signs of an overdose severe sedation, coma, seizures, or slow breathing.

If you notice any behavioral or physiological changes in your pet while giving diphenhydramine, contact your veterinarian immediately.

Additional information

Prescription Strength

25mg, 50mg

Package Size

100 Capsules, 100 Tablets, 1000 Capsules