Home/Medicines/Isoflurane
All medicines

Isoflurane

Prescription
Inhalant general anesthetic
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
4 available
Interactions
2 documented
Formulations
1

Mechanism of action

Produces general anesthesia by enhancing inhibitory GABA-A receptor activity and inhibiting excitatory NMDA receptors in the CNS; provides dose-dependent CNS depression with minimal metabolism (<0.2%)

At a glance

Class
Inhalant general anesthetic
Schedule
Prescription
Storage
Below 25°C, tightly sealed, no preservative needed; use calibrated vaporizer

Dosing

🐕

Dog

General anesthesia induction and maintenance
Dose
1.28–2.5 % MAC
Route
inhalation
Frequency
Continuous during procedure
Max dose
5 % for induction/dose; 0 % for induction/day
Duration: Duration of surgical procedure
🐈

Cat

General anesthesia induction and maintenance
Dose
1.63–2.5 % MAC
Route
inhalation
Frequency
Continuous during procedure
Max dose
5 % for induction/dose; 0 % for induction/day
Duration: Duration of surgical procedure

Formulations

🧴

Volatile liquid — 1

Strength
100%
Available in India

Storage

Below 25°C, tightly sealed, no preservative needed; use calibrated vaporizer

Safety

Absolute contraindications — do not use

  • Known susceptibility to malignant hyperthermia
    Sighthounds may have prolonged recovery
    Greyhound (sensitivity)

Use with caution

  • Severe hypovolemia
    May cause severe hypotension

Adverse effects

Common
Dose-dependent hypotension
Respiratory depression
Hypothermia
Serious
Malignant hyperthermia
Cardiac arrest (overdose)
Hepatotoxicity (very rare)

Monitoring parameters

SpO2ETCO2Heart rate and rhythm (ECG)Blood pressureBody temperatureAnesthetic depth

Interactions

Moderate — 2

Fentanyl
moderate
Fentanyl CRI reduces isoflurane MAC by 40-60% (MAC-sparing effect), allowing lower vaporizer settings and less cardiovascular depression from inhalant.
Management: Intended beneficial interaction. Reduce vaporizer setting and monitor depth. Standard balanced anesthesia technique.
Dexmedetomidine
moderate
Dexmedetomidine premedication reduces isoflurane MAC by 50-90%. Profound MAC reduction means very low vaporizer settings needed.
Management: Reduce isoflurane significantly when dexmedetomidine is on board. Monitor depth closely — over-anesthesia and hypotension risk.

Brands

International

Forane
Baxter
IsoFlo
Zoetis

India

Aerrane
Baxter India
Isoflurane
Piramal

FAQs

Frequently asked questions

›What is Isoflurane?
Isoflurane is a inhalant general anesthetic used in pets. Produces general anesthesia by enhancing inhibitory GABA-A receptor activity and inhibiting excitatory NMDA receptors in the CNS; provides dose-dependent CNS depression with minimal metabolism (<0.2%)
›What is Isoflurane used for in pets?
Isoflurane is used in veterinary medicine for: General anesthesia induction and maintenance.
›What is the Isoflurane dose for dogs?
For dogs, Isoflurane is typically dosed as follows — General anesthesia induction and maintenance: 1.28–2.5 % MAC inhalation Continuous during procedure. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Isoflurane dose for cats?
For cats, Isoflurane is typically dosed as follows — General anesthesia induction and maintenance: 1.63–2.5 % MAC inhalation Continuous during procedure. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What are the side effects of Isoflurane?
Common: Dose-dependent hypotension, Respiratory depression, Hypothermia. Serious (call your vet immediately): Malignant hyperthermia, Cardiac arrest (overdose), Hepatotoxicity (very rare).
›Does Isoflurane need a prescription?
Yes. Isoflurane is a prescription medication and should only be administered under veterinary supervision.
›When should Isoflurane not be used?
Do not use Isoflurane if: Known susceptibility to malignant hyperthermia.

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 →