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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

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)

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 →

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

Educational reference only

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.

Educational reference only

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.

Educational reference only

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

Plumb's Veterinary Drug Handbook
Withrow & MacEwen's Small Animal Clinical Oncology
Merck Veterinary Manual
NRC Nutrient Requirements of Dogs and Cats
Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

ASPCA Animal Poison Control Center Guidelines
AAHA Diabetes Management Guidelines
ASPCA Poison Control Guidelines
RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

EPIC Study (J Vet Intern Med 2016)
JVIM FAT CAT Study

Regulatory & approvals — 1

CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

Washington State University VCPL MDR1 Database