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Physostigmine

Prescription
Reversible Acetylcholinesterase Inhibitor (Carbamate)
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
1 available
Formulations
1

Mechanism of action

Tertiary amine carbamate that crosses the BBB and reversibly inhibits acetylcholinesterase in both peripheral and central nervous system. Used as antidote for anticholinergic toxicity (atropine, antihistamine, TCA overdose).

At a glance

Class
Reversible Acetylcholinesterase Inhibitor (Carbamate)
Schedule
Prescription
Storage
Store at room temperature; protect from light

Dosing

🐕

Dog

Antidote for anticholinergic syndrome (mydriasis, tachycardia, agitation, urinar
Dose
0.02–0.06 mg/kg
Route
IV (slow)
Frequency
q15–30 min (repeat as needed)
🐈

Cat

Same anticholinergic toxicity antidote use
Dose
0.02–0.04 mg/kg
Route
IV
Frequency
q15–30 min

Formulations

💊

Other — 1

Strength

Storage

Store at room temperature; protect from light

Safety

Monitoring parameters

Heart ratePupil size (miosis expected)Respiratory effortLevel of consciousnessHave atropine ready as reversal

Interactions

No documented interactions.

Brands

Other markets

Antilirium

FAQs

Frequently asked questions

What is Physostigmine?
Physostigmine is a reversible acetylcholinesterase inhibitor (carbamate) used in pets. Tertiary amine carbamate that crosses the BBB and reversibly inhibits acetylcholinesterase in both peripheral and central nervous system. Used as antidote for anticholinergic toxicity (atropine, antihistamine, TCA overdose).
What is Physostigmine used for in pets?
Physostigmine is used in veterinary medicine for: Antidote for anticholinergic syndrome (mydriasis, tachycardia, agitation, urinar; Same anticholinergic toxicity antidote use.
What is the Physostigmine dose for dogs?
For dogs, Physostigmine is typically dosed as follows — Antidote for anticholinergic syndrome (mydriasis, tachycardia, agitation, urinar: 0.02–0.06 mg/kg IV (slow) q15–30 min (repeat as needed). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Physostigmine dose for cats?
For cats, Physostigmine is typically dosed as follows — Same anticholinergic toxicity antidote use: 0.02–0.04 mg/kg IV q15–30 min. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Physostigmine need a prescription?
Yes. Physostigmine is a prescription medication and should only be administered under veterinary supervision.

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 →