Phenylephrine Hcl (phenylephrine HCl)

To produce decongestion of the conjunctiva, 1 or 2 drops of a 0.12-0.25% ophthalmic solution of phenylephrine hydrochloride may be applied topically to the conjunctiva every 3-4 hours (up to 4 times daily for self-medication) as needed. Vasoconstriction for diagnosis of ocular congestion or to improve visualization of ocular blood vessels in sickle-cell disease may be achieved by application of 1 or 2 drops of a 2.5% solution. In the ''blanching test'', congestion probably is caused by conjunctivitis rather than iridocyclitis if the drug produces perilimbal blanching in the congested eye. A 2.5 or 10% solution of the drug may also be administered prior to surgery to produce mydriasis and aid in controlling hemorrhage. (See Phenylephrine Hydrochloride 52:24.)

To produce nasal decongestion in adults and children 12 years of age or older, the usual dosage is 2 or 3 drops, 1-3 sprays, or 1-3 metered sprays instilled in each nostril. In cases of extreme nasal congestion in adults, a 1% solution may be used initially. To produce nasal decongestion in children 6-12 years of age, 2 or 3 drops or 1 or 2 sprays of a 0.25% solution may be instilled in each nostril. Doses of the drug as drops or spray may be repeated in 4 hours if needed. Phenylephrine nasal solutions should not be used for self-medication for longer than 3 days; if symptoms persist, the drug should be discontinued and a physician consulted. Intranasal application of phenylephrine should generally be used for no longer than 3-5 days.

For use with local anesthetics, phenylephrine hydrochloride may be used in concentrations of 1:2500 to 1:20,000.

Phenylephrine hydrochloride ophthalmic solutions are applied topically to the conjunctiva or cornea. A local anesthetic other than butacaine (See Chemistry and Stability: Stability) may be instilled prior to phenylephrine to prevent stinging and lacrimation.

Phenylephrine hydrochloride ophthalmic solutions are applied topically to the conjunctiva. Digital pressure should be applied on the lacrimal sac for 1-2 minutes following topical instillation of ophthalmic solutions to minimize drainage into the nose and throat and reduce the risk of absorption and systemic reactions. Excess solution around the eye should be removed with a tissue.

For intranasal applications, phenylephrine may be administered in solution as drops or spray. Vicks Sinex(R) (with mist spray nozzle) nasal solution is administered by nasal inhalation using a special nasal inhaler that produces metered droplet sprays. Care must be taken to avoid contamination of the dropper, inhaler, or spray. Except in young children in whom sprays are difficult to use, nasal sprays may be preferable to drops because of the lesser risk of swallowing the drug and resultant systemic absorption. Drops should be applied to the dependent (lower) nostril, with the patient in a lateral head-low position. The patient should remain in the same position for 5 minutes, then the solution should be applied to the other nostril in a similar manner. Alternatively, drops may be instilled when the patient is reclining with the head tilted back as far as possible. Sprays should be delivered or pumped (Vicks Sinex(R) metered spray) into each nostril with the patient's head erect so that excess solution is not released. The nose should be blown thoroughly 3-5 minutes later. Prior to initial use of the metered sprays, the nasal inhaler must be primed by depressing the pump firmly several times. To minimize the risk of spreading infections, droppers, inhalers, and spray dispensers should not be used by more than one person, and tips of the dispensers, inhalers, or droppers should be rinsed with hot water following use.

Phenylephrine nasal solutions also may be applied to a tampon or nasal pack for insertion into nasal passages. However, this method of application should be restricted to use in diagnostic or surgical procedures performed under medical supervision because mechanical injury may occur.

Concomitant administration of phenylephrine with cycloplegic antimuscarinic drugs such as atropine sulfate, cyclopentolate hydrochloride, homatropine hydrobromide, or scopolamine hydrobromide produces increased dilation of the pupil which is of clinical value.

Administration of a 10% solution of phenylephrine hydrochloride to patients pretreated with 2% pilocarpine hydrochloride produces mydriasis but to a lesser degree than occurs in patients who are not receiving the miotic. Pilocarpine may prevent or reduce visual disturbances and the risk of increased intraocular pressure associated with mydriasis in some patients and may be used to hasten recovery from mydriasis after ophthalmologic examination. Phenylephrine may reduce ciliary and conjunctival congestion and accommodative myopia often encountered when miotics are used alone in the treatment of glaucoma, without compromising the effectiveness of glaucoma therapy.

Phenylephrine must be administered under careful supervision and in reduced dosage if used within 21 days after the patient has received a monoamine oxidase inhibitor because potentiation of the pressor effects of phenylephrine may result. The pressor response to phenylephrine may also be potentiated if a tricyclic antidepressant is administered concomitantly.

If phenylephrine is administered to a patient undergoing chronic oral therapy with guanethidine, the pupillary response to phenylephrine is greatly increased and the pressor response may also be potentiated. Phenylephrine should be administered cautiously to patients receiving guanethidine.

The mydriatic response to phenylephrine is decreased in patients receiving levodopa.

When applied topically to the conjunctiva (especially in concentrations of 2.5% or greater), phenylephrine hydrochloride must be administered under careful supervision and in reduced dosage if used within 21 days after the patient has received a monoamine oxidase (MAO) inhibitor because potentiation of the pressor effects of phenylephrine may result. Nasal solutions containing phenylephrine must not be given to a patient receiving an MAO inhibitor. The pressor response to phenylephrine may also be potentiated if a tricyclic antidepressant is administered concomitantly.

Concomitant administration of phenylephrine with cycloplegic antimuscarinic drugs such as atropine sulfate, cyclopentolate hydrochloride, homatropine hydrobromide, or scopolamine hydrobromide produces increased mydriatic effects.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

Moderate Interaction: Assess the risk to the patient and take action as needed.

Sympathomimetics/Rauwolfia Alkaloids

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Reserpine depletes catecholamine stores within the peripheral vascular adrenergic nerve endings, thus indirect acting sympathomimetics are unable to trigger the release of catecholamines. The reserpine-induced catecholamine release increases sensitivity to the effects of direct acting sympathomimetics.

CLINICAL EFFECTS: Increased effects of direct acting sympathomimetics. Decreased effects of indirect acting sympathomimetics. Mixed acting sympathomimetics will show effects based on the predominance of either direct or indirect activity.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If these agents are administered concurrently, monitor blood pressure. The dose of the sympathomimetic may need to be adjusted.

DISCUSSION: This interaction has been well documented in animal studies and human case reports have confirmed the interaction. Reserpine has been shown to decrease the response to epinephrine administered for hypotension. Reserpine has also been shown to decrease the effectiveness of ophthalmic epinephrine, a direct acting sympathomimetic. Ophthalmic phenylephrine has been shown to decrease the hypotensive effects of reserpine.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

• Angle-closure glaucoma

• Atherosclerotic cardiovascular disease
• Benign prostatic hyperplasia
• Cardiac arrhythmia
• Coronary artery disease
• Diabetes mellitus
• Hypertension
• Hyperthyroidism

There is no enhanced messaging for this drug.

Rare or Very Rare

• Cardiac arrhythmia
• Dizziness
• Hyperhidrosis
• Hypertension
• Pallor
• Tachycardia
• Tremor

More Frequent

• Eye tearing
• Headache disorder
• Ocular irritation
• Ocular pain
• Photophobia

No enhanced messaging available.

No enhanced messaging available.

Animal reproduction studies have not been performed with phenylephrine. It is not known whether topically applied phenylephrine can cause fetal harm when administered to pregnant women. Parenterally administered phenylephrine in late pregnancy or labor may cause fetal anoxia. (See Cautions: Pregnancy and Lactation, in Phenylephrine Hydrochloride 12:12.04.) Topically applied phenylephrine should be used during pregnancy only when clearly needed.

Animal reproduction studies have not been performed with phenylephrine. It is not known whether topically applied phenylephrine can cause fetal harm when administered to pregnant women. Parenterally administered phenylephrine in late pregnancy or labor may cause fetal anoxia. (See Cautions: Pregnancy and Lactation, in Phenylephrine Hydrochloride 12:12.04.) Topically applied phenylephrine should be used during pregnancy only when clearly needed.

Since it is not known whether phenylephrine is distributed into milk, the drug should be used with caution in nursing women.

Since it is not known whether phenylephrine is distributed into milk, the drug should be used with caution in nursing women.

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