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Alfentanil

Ultra-Short-Acting Opioid Analgesic

Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team

Species

Dog, Cat

Brands

1 available

Interactions

2 documented

Formulations

Mechanism of action

Synthetic piperidine mu-opioid receptor agonist approximately 10–15x more potent than fentanyl on a per-dose basis for single bolus, but with much shorter duration (10–15 min). Rapid onset (1–2 min IV). Metabolized by CYP3A4.

At a glance

Class

Ultra-Short-Acting Opioid Analgesic

Schedule

Controlled Substance

Storage

Store at room temperature, protect from light

Dosing

🐕

Dog

Used for brief painful procedures (intubation, catheterization, short surgeries)

Dose

5–20 mcg/kg

Route

Frequency

Bolus q10–15 min or CRI

🐈

Cat

Same indications as dogs

Dose

5–10 mcg/kg

Route

Frequency

Bolus or 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 — 1

Strength

—

Storage

Store at room temperature, protect from light

Safety

Monitoring parameters

SpO2Respiratory rateHeart rateBlood pressurePain scores

Educational reference only

Interactions

Major — 2

Ketoconazole (Systemic)

major

Alfentanil is entirely CYP3A4 metabolized. Ketoconazole inhibits CYP3A4, dramatically increasing alfentanil levels and duration, causing prolonged respiratory depression.

Management: Reduce alfentanil dose by 50-75% if ketoconazole on board. Have ventilatory support ready. Monitor respiratory function closely.

Itraconazole

major

Itraconazole inhibits CYP3A4, significantly prolonging alfentanil effect and increasing respiratory depression risk.

Management: Reduce alfentanil dose. Monitor respiratory function. Have naloxone available.

Educational reference only

Brands

Other markets

Alfenta

FAQs

Frequently asked questions

›What is Alfentanil?

Alfentanil is a ultra-short-acting opioid analgesic used in pets. Synthetic piperidine mu-opioid receptor agonist approximately 10–15x more potent than fentanyl on a per-dose basis for single bolus, but with much shorter duration (10–15 min). Rapid onset (1–2 min IV). Metabolized by CYP3A4.

›What is Alfentanil used for in pets?

Alfentanil is used in veterinary medicine for: Used for brief painful procedures (intubation, catheterization, short surgeries); Same indications as dogs.

›What is the Alfentanil dose for dogs?

For dogs, Alfentanil is typically dosed as follows — Used for brief painful procedures (intubation, catheterization, short surgeries): 5–20 mcg/kg IV Bolus q10–15 min or CRI. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What is the Alfentanil dose for cats?

For cats, Alfentanil is typically dosed as follows — Same indications as dogs: 5–10 mcg/kg IV Bolus or CRI. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›Does Alfentanil need a prescription?

Alfentanil 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