Direct alpha-1 adrenergic agonist that contracts the iris dilator muscle causing mydriasis WITHOUT cycloplegia (no ciliary body effect). Short duration (3–6h). Used for diagnostic mydriasis and differentiation of anterior vs. posterior synechiae.
At a glance
Class
Ophthalmic Alpha-1 Adrenergic Agonist / Mydriatic
Storage
Store at room temperature, protect from light; discard if brown (oxidized)
Dosing
Used for diagnostic fundoscopy (shorter mydriasis than atropine — 3–6h)
Frequency
Once for diagnostic; q4–6h if therapeutic
Use only 2
Frequency
Once for diagnostic
Safety
Pupil dilation responseBlood pressure (10% solution)IOP (glaucoma risk)
Interactions
No documented interactions.
Brands
Other markets
Neo-Synephrine Ophthalmic
FAQs
Frequently asked questions
›What is Phenylephrine Ophthalmic?
Phenylephrine Ophthalmic is a ophthalmic alpha-1 adrenergic agonist / mydriatic used in pets. Direct alpha-1 adrenergic agonist that contracts the iris dilator muscle causing mydriasis WITHOUT cycloplegia (no ciliary body effect). Short duration (3–6h). Used for diagnostic mydriasis and differentiation of anterior vs. posterior synechiae.
›What is Phenylephrine Ophthalmic used for in pets?
Phenylephrine Ophthalmic is used in veterinary medicine for: Used for diagnostic fundoscopy (shorter mydriasis than atropine — 3–6h); Use only 2.
›What is the Phenylephrine Ophthalmic dose for dogs?
For dogs, Phenylephrine Ophthalmic is typically dosed as follows — Used for diagnostic fundoscopy (shorter mydriasis than atropine — 3–6h): undefined undefined Ophthalmic Once for diagnostic; q4–6h if therapeutic. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Phenylephrine Ophthalmic dose for cats?
For cats, Phenylephrine Ophthalmic is typically dosed as follows — Use only 2: undefined undefined Ophthalmic Once for diagnostic. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Phenylephrine Ophthalmic need a prescription?
Yes. Phenylephrine Ophthalmic 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 →