Concise Prescribing Info
Phenylephrine HCl 25 mg/mL
Vasoconstrictor, decongestant, & mydriatic in ophth conditions & procedures eg, for pupillary dilation in uveitis (to prevent or aid in the disruption of posterior synechia formation), for many ophth surgical procedures & for refraction w/o cycloplegia. Funduscopy & other diagnostic procedures.
Dosage/Direction for Use
Vasoconstriction & pupil dilation 1 drop of topical anesth may be applied, followed in a few min by 1 drop of Mydfrin on the upper limbus. Repeat the installation after 1 hr if necessary, again preceded by the use of the topical anesth. Uveitis 1 drop to the upper surface of cornea & may be repeated if necessary, not to exceed 3 times. Surgery Apply 30-60 min pre-op. Refraction Adult 1 drop of the preferred cycloplegic in each eye, followed in 5 min by 1 drop of Mydfrin. Childn For a 1 application method, may be combined w/ 1 of the preferred rapid acting cycloplegics to produce adequate cycloplegia. Ophthalmoscopic exam 1 drop in each eye. Blanching test 1-2 drops applied to the injected eye.
Hypersensitivity. Anatomically narrow angles or narrow angle glaucoma. Intraocular procedures when the corneal epithelial barrier has been disturbed. Newborn, infants & elderly w/ severe arteriosclerotic CV or cerebrovascular disease.
Special Precautions
May cause allergic-type reactions. Sulfite sensitive patients. Do not use intraocularly. Sympathetic denervation (eg, patients w/ insulin dependent diabetes, orthostatic hypotension, HTN, hyperthyroidism). Concomitant use w/ MAOIs, TCAs, certain antihypertensive agents or atropine. Benzalkonium Cl content may cause irritation & discolor soft contact lenses. Avoid contact w/ soft contact lenses. May raise IOP. Rebound miosis. May liberate pigment granules from the iris. Prolonged exposure to air or strong light may cause oxidation & discoloration. Do not use if soln is brown or contains a precipitate. Instrumented, traumatized, diseased or post-op eye or adnexa or to patients w/ suppressed lacrimation. May impair the ability to drive or operate machinery. Pregnancy & lactation. Monitor BP in elderly patients w/ cardiac disease. Infants w/ known cardiac anomalies.
Adverse Reactions
Marked increase in BP. Elderly: CV reactions including syncope, MI, tachycardia, arrhythmia & fatal subarachnoid hemorrhage.
Drug Interactions
May result to exaggerated adrenergic effects w/ co-administration of MAOIs. Potentiated pressor response w/ TCAs & certain antihypertensives (guanethidine, reserpine & non-selective β-blockers eg, propranolol). Enhance pressor effects & induce tachycardia w/ concomitant use of atropine. May potentiate CV depressant effects of potent inhalation anesth.
MIMS Class
Mydriatic Drugs
ATC Classification
S01FB01 - phenylephrine ; Belongs to the class of sympathomimetics used as mydriatics and cycloplegics.
Mydfrin ophth soln 2.5%
5 mL x 1's
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