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Naphazoline (52:32) - 382268

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Naphazoline Hydrochloride

AHFS Class: Vasoconstrictors (52:32)

ATC Class: S01GA01
VA Class: OP800

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View the associated Essentials monograph.

Introduction

Naphazoline hydrochloride, an imidazoline derivative sympathomimetic amine, is a vasoconstrictor.

Uses

Naphazoline is applied topically to the conjunctiva to temporarily relieve congestion, itching, and minor irritation. Ocular decongestants are ineffective in the treatment of delayed hypersensitivity reactions such as contact dermatoconjunctivitis. The vasoconstrictor effects of naphazoline may be used during some ocular diagnostic procedures, but some clinicians prefer phenylephrine to naphazoline for this use.

Ophthalmic solutions containing naphazoline in combination with antihistamines such as antazoline phosphate or pheniramine maleate and/or astringents such as zinc sulfate are commercially available. In the concentrations usually employed, zinc sulfate is a relatively ineffective antiseptic and may promote vasodilation.

Dosage and Administration

Administration

Ophthalmic solutions of naphazoline hydrochloride are applied topically to the conjunctiva. Care must be taken to avoid contamination of the dropper tip. Some manufacturers recommend that contact lenses be removed before administration of ophthalmic solutions containing naphazoline.

Dosage

Conjunctival Congestion

To produce decongestion of the conjunctiva, 1–2 drops of a 0.1% ophthalmic solution of naphazoline hydrochloride may be applied topically to the conjunctiva every 3–4 hours as needed or 1 or 2 drops of a 0.01–0.03% ophthalmic solution may be applied topically to the conjunctiva up to 4 times daily or as directed by a physician.

Cautions

Adverse Effects

The incidence of serious adverse effects is low in patients receiving therapeutic dosages of ophthalmic solutions of naphazoline hydrochloride. When naphazoline hydrochloride is used in combination preparations, the cautions applicable to each ingredient in the formulation must be observed. Excessive dosage and/or prolonged or too frequent use may irritate the conjunctiva and, especially in children, cause adverse systemic effects.

Use of naphazoline in the eye may cause blurred vision, mild transient stinging and/or irritation, mydriasis, and increased or decreased intraocular pressure. Conjunctival application of naphazoline, especially when high concentrations are used in geriatric patients, may liberate pigment granules, presumably from the iris. Rebound congestion, characterized by reactive hyperemia frequently occurs with prolonged use and may result in overuse of the drug. Prolonged use of the drug should be avoided for these reasons.

Ophthalmic use of naphazoline may occasionally cause systemic sympathomimetic effects such as headache, hypertension, cardiac irregularities, nervousness, nausea, dizziness, weakness, and sweating. Overdosage of the drug may produce drowsiness, decreased body temperature, bradycardia, shock-like hypotension, and coma.

Precautions and Contraindications

Naphazoline hydrochloride ophthalmic solution should be used with caution in patients with hypertension, cardiovascular abnormalities, diabetes mellitus, hyperthyroidism, infection, or injury.

Patients using naphazoline hydrochloride ophthalmic solutions should be advised to discontinue the drug and consult a physician if ocular pain or visual changes occur, they experience continued ocular redness or irritation, the condition worsens or persists for more than 48 hours, or they experience manifestations of systemic absorption (e.g., headache, nausea, decrease in body temperature). Patients also should be informed that overuse of ophthalmic vasoconstrictors may produce increased redness of the eye (rebound hyperemia).

Naphazoline is contraindicated in patients with known hypersensitivity to the drug. Patients with glaucoma should be advised not to use naphazoline hydrochloride ophthalmic solutions except under the advice and supervision of a physician. Ophthalmic solutions of the drug should not be used in patients with angle-closure glaucoma. Fixed combinations containing naphazoline hydrochloride and antazoline are contraindicated while soft contact lenses are being worn.

Pediatric Precautions

Excessive dosage of topically applied naphazoline hydrochloride may cause marked sedation in children, and, if severe, symptomatic and supportive therapy should be initiated. One manufacturer states that 0.1% naphazoline hydrochloride ophthalmic solution is contraindicated in infants and children, since CNS depression possibly progressing to coma and hypothermia may occur in children, especially infants.

Pregnancy, Fertility, and Lactation

Pregnancy

Animal studies have not been conducted with naphazoline hydrochloride, and it is not known whether the drug can cause fetal harm when administered to a pregnant woman. Therefore, naphazoline hydrochloride should be used during pregnancy only when clearly needed.

Fertility

It is not known whether naphazoline hydrochloride can affect reproduction capacity in humans.

Lactation

It is not known whether naphazoline hydrochloride is distributed into milk. Because many drugs are distributed into milk, caution should be exercised when this drug is administered to a breast-feeding woman.

Drug Interactions

Concurrent use of maprotiline or tricyclic antidepressants with naphazoline hydrochloride may potentiate the pressor effects of naphazoline.

Patients being treated with monoamine oxidase (MAO) inhibitors may experience a severe hypertensive reaction if administered with a sympathomimetic drug. Although this reaction has not specifically been reported with naphazoline, the possibility of such an interaction should be considered.

Pharmacology

The mechanism of action of naphazoline has not been conclusively determined. Most pharmacologists believe that the drug directly stimulates α-adrenergic receptors of the sympathetic nervous system and exerts little or no effect on β-adrenergic receptors. Following topical application of naphazoline to the conjunctiva, small arterioles are constricted and conjunctival congestion is temporarily relieved, but reactive hyperemia may occur. The drug also may produce mydriasis when applied to the conjunctiva, but this effect is usually minimal with the concentrations used as ocular decongestants.

Pharmacokinetics

Following topical application of naphazoline hydrochloride solutions to the conjunctiva, local vasoconstriction usually occurs within 10 minutes and may persist for 2–6 hours. Occasionally, enough naphazoline may be absorbed to produce systemic effects. Information on the distribution and elimination of the drug in humans is not available.

Chemistry and Stability

Chemistry

Naphazoline hydrochloride is an imidazoline derivative sympathomimetic amine which is structurally and pharmacologically related to oxymetazoline, tetrahydrozoline, and xylometazoline. Naphazoline hydrochloride occurs as a white, odorless, crystalline powder having a bitter taste and is freely soluble in water and in alcohol. Naphazoline hydrochloride ophthalmic solutions are sterile, buffered solutions of the drug in water adjusted to a suitable pH and tonicity; the commercially available ophthalmic solutions also contain a suitable preservative (e.g., benzalkonium chloride). Naphazoline hydrochloride ophthalmic solutions have a pH of 5.5–7.

Stability

Naphazoline hydrochloride ophthalmic solutions should be protected from light and should be stored in tight, light-resistant containers. The drug is degraded in the presence of aluminum and, therefore, should not be stored in aluminum containers. Discolored or cloudy solutions of the drug should not be used. Fixed combinations containing naphazoline hydrochloride and antazoline phosphate should be stored at temperatures less than 25°C.

Preparations

Naphazoline Hydrochloride

Routes Forms Strengths Brand Names Manufacturer

Ophthalmic
Solution

0.012%

All Clear^® (with benzalkonium chloride)
Bausch & Lomb

Clear Eyes^® (with benzalkonium chloride and glycerin 0.2%)
Prestige Brands

Naphcon^® (with benzalkonium chloride)
Alcon

0.03%

All Clear^® AR (with benzalkonium chloride)
Bausch & Lomb

0.1%*

AK-Con^® (with benzalkonium chloride)
Akorn

Albalon^® (with benzalkonium chloride)
Allergan

Naphazoline Hydrochloride Ophthalmic Solution^®
Bausch & Lomb

* available by nonproprietary name

Naphazoline Hydrochloride Combinations

Routes Forms Strengths Brand Names Manufacturer

Ophthalmic
Solution

0.012% with Zinc Sulfate 0.25%

Clear Eyes^® ACR (with benzalkonium chloride and glycerin 0.2%)
Prestige Brands

0.025% with Pheniramine Maleate 0.3%

Naphcon-A^® (with benzalkonium chloride)
Alcon

Visine A^®
Pfizer

0.027% with Pheniramine Maleate 0.315%

Opcon A^®
Bausch & Lomb

0.05% with Antazoline Phosphate 0.5%

Vasocon-A^® (with benzalkonium chloride)
Novartis

Comparative Pricing

This pricing information is subject to change at the sole discretion of DS Pharmacy. For the most current and up-to-date pricing information, please visit www.drugstore.com.

Albalon 0.1% Solution (ALLERGAN): 15/$29.99 or 45/$75.97