Major Uses

Hydromorphone is used in dogs and cats as a sedative, restraining agent, analgesic or preanesthetic. The drug is usually less sedating than morphine and rarely causes vasodilation and hypotension. However, there have been more incidences during testing of nausea and vomiting than with morphine.

Common Precautions

Hydromorphone is an opiate and should be used with caution in patients with hypothyroidism, Addison's disease, or severe renal insufficiency. Caution should also be used in geriatric or severely debilitated animals. Any animal that is suspected of gastric dilation, volvulus, or intestinal obstruction should be evaluated before taking hydromorphone due to the fact it may cause vomiting. Hydromorphone should be considered with extreme caution for animals with head injuries, increased intracranial pressure and acute abdominal conditions because of the possibility of the drug complicating the diagnosis or clinical course of these conditions.

Dogs have been noted to become sedated, whine, pant, become more vocal, vomit and defecate while taking hydromorphone. There is a possibility of dose related respiratory depression. A cat's body temperature can increase, which can last up to five hours. Hypothermia has been reported in cats, as well as bizarre behavioral changes. Hydromorphone can also cause bradycardia in the animals.

Hydromorphone should not be used in animals with a known allergy or hypersensitivity to the drug.


The injection and tablet form should be stored at room temperature in a light resistant container. The injection remains stable for at least 24 hours when mixed with IV fluids if protected from light. Suppositories need to be kept in the refrigerator.


Hydromorphone is available in oral, injectable and suppository form. After the drug is given to dogs, the peak levels occur between 10-30 minutes after dosing. Hydromorphone is five times more potent as an analgesic on a per weight basis when compared to morphine.

A typical dose of hydromorphone for dogs using an IV is 0.02-0.1 mg/kg, every two to four hours. When using an IM or SC injection, 0.05-0.2 mg/kg is used for every two to six hours. A typical dose for a cat using an IV, IM or SC injection is 0.05-0.1 mg/kg every two to six hours.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.