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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
1

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
IV
Frequency
Bolus q10–15 min or CRI
🐈

Cat

Same indications as dogs
Dose
5–10 mcg/kg
Route
IV
Frequency
Bolus or CRI

Formulations

💊

Other — 1

Strength
—

Storage

Store at room temperature, protect from light

Safety

Monitoring parameters

SpO2Respiratory rateHeart rateBlood pressurePain scores

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.

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.

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 →