ExoticRx · exoticrx.com/drugs/phenylephrine-ophthalmic
US brand names:Mydfrin, Neo-Synephrine Ophthalmic
Alpha-1 adrenergic agonist causing contraction of iris dilator muscle (mydriasis) without cycloplegia. Also causes conjunctival vasoconstriction.
10% concentration can cause systemic hypertension — use 2.5% in small animals. Mydriasis without cycloplegia (pupil still accommodates). Avoid in narrow-angle glaucoma.
Species references:All Cat (Domestic) drugsAll Dog (Domestic) drugs
Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.
A dog/cat sample is shown here. Cited dosing for all 2 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.
| Species | Route | Dose | Frequency | Evidence | Source |
|---|---|---|---|---|---|
| Dog (Domestic) | TOPICAL (ophthalmic) | Use 2.5% in small animals (10% can cause systemic hypertension) | PRN for exam or q6-8h therapeutic | Moderate | Plumb's Veterinary Drug Handbook, 9th Ed |
| Cat (Domestic) | TOPICAL (ophthalmic) | 2.5% only in cats | PRN for exam or q6-8h | Moderate | Plumb's Veterinary Drug Handbook, 9th Ed |
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