Emedastine

Class: Antiallergic Agents
- Histamine H1-receptor Antagonists
ATC Class: S03AA07
VA Class: OP900
Chemical Name: 1-(2-Ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)benzimidazole fumerate (1:2)
Molecular Formula: C₁₇H₂₆N₄O•2C₄H₄O₄
CAS Number: 87233-62-3
Brands: Emadine

Medically reviewed by Drugs.com. Last updated on June 22, 2020.

• Overview
• Side Effects
• Dosage
• Professional
• Pregnancy
• More

Introduction

Relatively selective histamine H₁-receptor antagonist;^{1 2 3 14} a benzimidazole derivative.^{1 12}

Uses for Emedastine

Allergic Conjunctivitis

Symptomatic relief of allergic conjunctivitis.¹

Emedastine Dosage and Administration

Administration

Apply topically to the eye as an ophthalmic solution.¹ Not for injection or oral use.¹

Ophthalmic Administration

Remove soft contact lenses prior to administration of each dose (since benzalkonium chloride preservative may be absorbed by the lenses); may reinsert lenses 10 minutes after administration if eyes are not red.¹

If more than one topical ophthalmic drug is used, administer the drugs at least 5 minutes apart.¹²

Avoid contamination of the solution container.¹

Do not use if solution is discolored.¹

Dosage

Available as emedastine difumarate; dosage expressed in terms of emedastine.¹

Pediatric Patients

Allergic Conjunctivitis

Ophthalmic

Children ≥3 years of age: 1 drop of a 0.05% solution in the affected eye(s) up to 4 times daily.¹

Adults

Allergic Conjunctivitis

Ophthalmic

1 drop of a 0.05% solution in the affected eye(s) up to 4 times daily.¹

Cautions for Emedastine

Contraindications

• Known hypersensitivity to emedastine or any ingredient in the formulation.¹

Warnings/Precautions

Specific Populations

Pregnancy

Category B.¹

Lactation

Distributed into milk in rats following oral administration;¹ not known whether distributed into human milk following topical application to the eye.¹ Use with caution.¹

Pediatric Use

Safety and efficacy not established in children <3 years of age.¹

Adverse effect profile in children 3–16 years of age is similar to that in individuals ≥17 years of age.¹⁴

Geriatric Use

No substantial differences in safety and efficacy relative to younger adults.¹

Common Adverse Effects

Headache.¹

Interactions for Emedastine

No formal drug interaction studies to date.¹²

Emedastine Pharmacokinetics

Absorption

Bioavailability

Limited systemic exposure following topical application to the eye;¹ plasma concentrations usually are undetectable.^{1 12}

Onset

Rapid onset.^{2 14}

Duration

Long duration.^{2 14}

Elimination

Metabolism

Metabolized in the liver principally to 5- and 6-hydroxyemedastine following oral administration; metabolites appear to undergo further oxidation to form 5′-oxo analogs.^{1 12}

Elimination Route

44% of an oral dose is recovered in urine within 24 hours.¹

Half-life

3–4 hours following oral administration.¹

Stability

Storage

Ophthalmic

Solution

Tightly closed bottle at 4–30°C.¹

Actions

• Inhibits the histamine-stimulated conjunctival vascular permeability response in a concentration-dependent manner.^{1 2}

• Potency is about 100, 357, or 5813 times that of levocabastine, pheniramine, or antazoline, respectively, on a molar basis.^{2 14}

Advice to Patients

• Importance of learning and adhering to proper administration techniques to avoid contamination of the solution container.^{1 12}

• Importance of removing soft contact lenses prior to administration of each dose.¹ Delay reinsertion for 10 minutes after administration if eyes are not red; do not wear contact lenses if eye(s) are red.¹ Not indicated for contact lens-related irritation.¹

• Importance of administering different topical ophthalmic preparations at least 5 minutes apart.¹

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.¹

• Importance of informing clinicians of existing or contemplated therapy, including prescription and OTC drugs as well as any concomitant illnesses.

• Importance of informing patients of other important precautionary information.¹ (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

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