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Hydromorphone

Full Mu-Opioid Agonist
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
1 available
Interactions
4 documented
Formulations
2

Mechanism of action

Semi-synthetic opioid 5–7x more potent than morphine. Full mu-opioid receptor agonist providing potent analgesia without significant histamine release (unlike morphine). Rapid onset with intermediate duration.

At a glance

Class
Full Mu-Opioid Agonist
Schedule
Controlled Substance
Storage
Store at room temperature, protect from light; controlled substance secure storage

Dosing

🐕

Dog

Excellent perioperative and emergency analgesic
Dose
0.05–0.2 mg/kg
Route
IV, IM, SQ
Frequency
q2–4h (bolus); continuous (CRI)
🐈

Cat

Preferred full mu-agonist in cats — less vomiting and dysphoria than morphine
Dose
0.025–0.1 mg/kg
Route
IV, IM, SQ
Frequency
q4–6h (bolus); continuous (CRI)

Formulations

💊

Other — 2

Strength
—
Strength
—

Storage

Store at room temperature, protect from light; controlled substance secure storage

Safety

Monitoring parameters

Respiratory rateSpO2Pain scoresTemperature (cats)Heart rateSedation level

Interactions

Major — 1

Buprenorphine
major
Buprenorphine's high mu-receptor affinity and partial agonist ceiling effect blocks hydromorphone from achieving full analgesia.
Management: Do not combine. Allow buprenorphine to wear off (4-6h) before full mu-agonist.

Moderate — 3

Acepromazine
moderate
Additive sedation, respiratory depression, and hypotension. Alpha-1 blockade (acepromazine) + opioid vasodilation/bradycardia.
Management: Intended premedication combination — reduce doses of both by 25-50%. Monitor BP and respiratory rate.
Midazolam
moderate
Synergistic sedation and respiratory depression. Commonly used as balanced premedication.
Management: Standard combination — reduce individual doses. Have intubation equipment ready.
Gabapentin
moderate
Additive CNS depression and sedation. Gabapentin enhances opioid analgesia synergistically but increases sedation.
Management: Beneficial multimodal combination. Start gabapentin at lower dose when adding to opioid. Monitor sedation in geriatric patients.

Brands

Other markets

Dilaudid

FAQs

Frequently asked questions

›What is Hydromorphone?
Hydromorphone is a full mu-opioid agonist used in pets. Semi-synthetic opioid 5–7x more potent than morphine. Full mu-opioid receptor agonist providing potent analgesia without significant histamine release (unlike morphine). Rapid onset with intermediate duration.
›What is Hydromorphone used for in pets?
Hydromorphone is used in veterinary medicine for: Excellent perioperative and emergency analgesic; Preferred full mu-agonist in cats — less vomiting and dysphoria than morphine.
›What is the Hydromorphone dose for dogs?
For dogs, Hydromorphone is typically dosed as follows — Excellent perioperative and emergency analgesic: 0.05–0.2 mg/kg IV/IM/SQ q2–4h (bolus); continuous (CRI). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Hydromorphone dose for cats?
For cats, Hydromorphone is typically dosed as follows — Preferred full mu-agonist in cats — less vomiting and dysphoria than morphine: 0.025–0.1 mg/kg IV/IM/SQ q4–6h (bolus); continuous (CRI). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Hydromorphone need a prescription?
Hydromorphone is available over the counter. Even so, you should consult your veterinarian before giving any medication to your pet.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →