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Phenylephrine (Ophthalmic)

Generic name: phenylephrine ophthalmic

Brand names: AK-Dilate, Neofrin, Altafrin, Mydfrin, Relief, Isopto Frin, AK-Nefrin, Neo-Synephrine Ophthalmic, Phenoptic, Prefrin, Ocu-Phrin, Refresh Redness Relief

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Solution, Ophthalmic, as hydrochloride:

Altafrin: 2.5% (15 mL); 10% (5 mL) [contains benzalkonium chloride]

Generic: 2.5% (2 mL, 3 mL [DSC], 5 mL [DSC], 15 mL); 10% (5 mL)

Solution, Ophthalmic, as hydrochloride [preservative free]:

Generic: 2.5% (1 ea [DSC])


Mechanism of Action

Potent, direct-acting alpha-adrenergic agonist with virtually no beta-adrenergic activity; produces local vasoconstriction. When applied topically to the eye, phenylephrine stimulates the dilator muscle of the iris, resulting in mydriasis.



Minimal systemic absorption (Kumar 1986)

Onset of Action

Mydriasis: 15 minutes; maximal mydriasis: 20 to 90 minutes; time to recovery: 3 to 8 hours

Time to Peak

Plasma: ≤20 minutes (Kumar 1986)

Use: Labeled Indications

Mydriasis: Pharmacologic dilation of pupils.


2.5% solution: There are no contraindications listed in the manufacturer's labeling.

10% solution: Hypertension; thyrotoxicosis; infants younger than 1 year.

Dosage and Administration

Dosing: Adult

Mydriasis: Ophthalmic: 2.5% or 10% solution: Instill 1 drop every 3 to 5 minutes as needed (maximum dose: 3 drops per eye). If necessary, dose may be repeated.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Mydriasis: Ophthalmic:

2.5% Solution: Infants, Children, and Adolescents: Instill 1 drop 15 to 30 minutes prior to procedure; administer every 3 to 5 minutes; maximum total dose: 3 drops per eye (AAP 2008)

10% Solution: Children and Adolescents: Instill 1 drop 15 to 30 minutes prior to procedure; administer every 3 to 5 minutes as needed; maximum total dose: 3 drops per eye


Ophthalmic: Wash hands before and after application. For topical ophthalmic use only; to avoid contamination, do not touch dropper tip to eyelids or other surfaces when placing drops in eyes. Solution should be applied to the conjunctival fornix unless otherwise directed. Protect eyes from bright illumination while pupils are dilated. Use of finger to occlude tear duct following instillation reduces systemic exposure. Topical ophthalmic phenylephrine may contain a preservative that can discolor soft contact lenses. Patients should remove contacts prior to drop instillation and wait at least 15 minutes before reinsertion.


Ophthalmic solution: 2.5% and 10%: Refer to product labeling. Some products are labeled to store at room temperature; others should be stored under refrigeration at 2°C to 8°C (36°F to 46°F). Do not use solution if brown or contains a precipitate.

Drug Interactions

Alpha1-Blockers: May diminish the vasoconstricting effect of Alpha1-Agonists. Similarly, Alpha1-Agonists may antagonize Alpha1-Blocker vasodilation. Monitor therapy

AtoMOXetine: May enhance the hypertensive effect of Sympathomimetics. AtoMOXetine may enhance the tachycardic effect of Sympathomimetics. Monitor therapy

Cannabinoid-Containing Products: May enhance the tachycardic effect of Sympathomimetics. Exceptions: Cannabidiol. Monitor therapy

Cocaine (Topical): May enhance the hypertensive effect of Sympathomimetics. Management: Consider alternatives to use of this combination when possible. Monitor closely for substantially increased blood pressure or heart rate and for any evidence of myocardial ischemia with concurrent use. Consider therapy modification

Doxofylline: Sympathomimetics may enhance the adverse/toxic effect of Doxofylline. Monitor therapy

Ergot Derivatives: May enhance the hypertensive effect of Alpha1-Agonists. Ergot Derivatives may enhance the vasoconstricting effect of Alpha1-Agonists. Exceptions: Ergoloid Mesylates; Nicergoline. Avoid combination

Guanethidine: May enhance the arrhythmogenic effect of Sympathomimetics. Guanethidine may enhance the hypertensive effect of Sympathomimetics. Monitor therapy

Iobenguane Radiopharmaceutical Products: Alpha1-Agonists may diminish the therapeutic effect of Iobenguane Radiopharmaceutical Products. Management: Discontinue all drugs that may inhibit or interfere with catecholamine transport or uptake for at least 5 biological half-lives before iobenguane administration. Do not administer these drugs until at least 7 days after each iobenguane dose. Avoid combination

Linezolid: May enhance the hypertensive effect of Sympathomimetics. Management: Reduce initial doses of sympathomimetic agents, and closely monitor for enhanced pressor response, in patients receiving linezolid. Specific dose adjustment recommendations are not presently available. Consider therapy modification

Monoamine Oxidase Inhibitors: May enhance the hypertensive effect of Alpha1-Agonists. While linezolid is expected to interact via this mechanism, management recommendations differ from other monoamine oxidase inhibitors. Refer to linezolid specific monographs for details. Exceptions: Linezolid. Avoid combination

Solriamfetol: Sympathomimetics may enhance the hypertensive effect of Solriamfetol. Monitor therapy

Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics. Monitor therapy

Tedizolid: May enhance the hypertensive effect of Sympathomimetics. Tedizolid may enhance the tachycardic effect of Sympathomimetics. Monitor therapy

Tricyclic Antidepressants: May enhance the therapeutic effect of Alpha1-Agonists. Tricyclic Antidepressants may diminish the therapeutic effect of Alpha1-Agonists. Monitor therapy

Adverse Reactions

Frequency not defined. Systemic effects are rare at normal dosages.

Ophthalmic: Burning sensation of eyes, eye irritation, miosis (rebound), visual disturbance, vitreous opacity (transient)

<1%, postmarketing, and/or case reports: Cardiac arrhythmia, hypertension, myocardial infarction, subarachnoid hemorrhage, syncope


Concerns related to adverse effects:

  • Cardiovascular events: Although rare, ventricular arrhythmias and myocardial infarction (including fatalities) have been reported with use of the 10% solution. Patients with preexisting cardiovascular disease may be at increased risk; consider use of 2.5% solution in these patients.
  • Hypertension: Significant blood pressure elevation has been reported with the 10% solution; risk is less with 2.5% solution. Use caution when using 10% solution in children <5 years of age, patients with hyperthyroidism or patients with cardiovascular disease. Carefully monitor posttreatment blood pressure in patients with endocrine or cardiac diseases, or any patient who develops symptoms during treatment.
  • Rebound miosis: Has been reported 1 day after treatment; reinstallation of the drug produced a lesser mydriatic effect.

Special populations:

  • Pediatrics: The 10% should NOT be used in infants <1 year of age (2.5% solution should be used). Use caution when using 10% solution in children <5 years of age.

Concurrent drug therapy issues:

  • Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Other warnings/precautions:

  • Appropriate use: For ophthalmic use only; not for injection.
  • Driving: Topical ophthalmic phenylephrine may cause blurring of vision. Patients should be cautioned about driving or operating machinery following dosing.
  • Sulfites: Some products contain sulfites which may cause allergic reactions in susceptible individuals.


Pregnancy Risk Factor


Pregnancy Considerations

Animal reproduction studies have not been conducted; therefore, the manufacturer classifies phenylephrine ophthalmic as pregnancy category C. When administered intravenously, phenylephrine crosses the placenta (refer to the Phenylephrine (Systemic) monograph for details). The amount of phenylephrine available systemically following ophthalmic application is generally less in comparison to oral or IV doses.

Patient Education

  • Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
  • Patient may experience stinging, eye pain, eye irritation, blurred vision, or sensitivity to light. Have patient report immediately to prescriber severe headache, dizziness, passing out, vision changes, chest pain, fast heartbeat, abnormal heartbeat, or signs of severe cerebrovascular disease (change in strength on one side is greater than the other, difficulty speaking or thinking, change in balance, or vision changes (HCAHPS).
  • Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Source: Wolters Kluwer Health. Last updated January 10, 2020.