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
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 →Safety
Pupil dilation responseBlood pressure (10% solution)IOP (glaucoma risk)
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 →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.
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 →References
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