Emedastine is a sterile, ophthalmic solution for topical application to the eyes for the treatment of allergic conjunctivitis. Emedastine is not intended to treat contact lens related irritation. The commercial product formulation has a pH of approximately 7.4 and an osmolality of approximately 300 mOsm/kg. Emedastine (Emadine(R)) was approved by the FDA in December 1997.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
-Emedastine is administered topically to the eye.
-Wash hands before and after use. Tilt the head back slightly and pull the lower eyelid down with the index finger. Instill the prescribed number of drops into the conjunctival sac and gently close eyes for 1-2 minutes. Do not blink.
-Care should be taken to avoid contamination. Do not touch the tip of the dropper to the eye, fingertips, or other surface.
-Patients should wait at least ten minutes after instilling the ophthalmic solution before inserting contact lenses.
-Do not share ophthalmic drops between patients.
In controlled clinical studies of emedastine lasting for 42 days, the most frequent adverse reaction was headache (11%). Other adverse reactions that were reported in < 5% of patients included abnormal dreams, asthenia, blurred vision, corneal deposits or staining, dermatitis, dysgeusia, hyperemia, keratitis, lacrimation, ocular irritation (burning, discomfort, foreign body sensation, or stinging), xerophthalmia (dry eye), pruritus, rhinitis, and sinusitis. Some of these adverse reactions were similar to the underlying disease being studied.
Emedastine is contraindicated for use in patients with a known history of hypersensitivity to emedastine or other product ingredients. Emedastine ophthalmic solution is formulated with the preservative benzalkonium chloride, which may be absorbed by soft contact lenses. Users of soft contact lenses should not administer emedastine while wearing contact lenses. Contact lens wearers should wait at least 10 minutes after using emedastine before inserting their lenses. Do not use emedastine to treat contact lens related ocular irritation.
The safety and effectiveness of emedastine in neonates, infants, and children less than 3 years of age have not been established.
Emedastine is classified as FDA pregnancy risk category B. There are no adequate and well-controlled studies in pregnant women, and its ability to cause fetal harm or affect reproductive capacity is unknown. Animal studies have failed to revealed any teratogenic effects at concentrations 15,000-times the maximum recommended ocular human concentration. Because animal studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Data are limited regarding use of emedastine during breast-feeding, and its excretion into human milk is unknown. The manufacturer advises caution when administering to lactating mothers; however, exposure of a nursing infant is considered unlikely because systemic absorption is generally below detectable limits (< 0.3 ng/ml) when administered via the ophthalmic route. To minimize the amount of drug that may reach systemic circulation and breast milk, instruct the patient to apply pressure over the tear duct by the corner of the eye for 1 minute after each administration. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, health care providers are encouraged to report the adverse effect to the FDA.
For the temporary relief of the signs and symptoms (e.g., ocular pruritus) of allergic conjunctivitis:
Adults, Adolescents, and Children >= 3 years: 1 drop in the affected eye(s) up to 4 times per day.
Children < 3 years: Safety and efficacy have not been established.
Maximum Dosage Limits:
4 drops/day ophthalmic solution in each affected eye.
4 drops/day ophthalmic solution in each affected eye.
4 drops/day ophthalmic solution each affected eye.
>= 3 years: 4 drops/day ophthalmic solution in each affected eye.
< 3 years: Safety and efficacy have not been established.
Patients with Hepatic Impairment Dosing
Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.
Patients with Renal Impairment Dosing
Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.
There are no drug interactions associated with Emedastine products.
Emedastine is a relatively selective antagonist at H1-receptors. Following topical ocular administration, emedastine blocks H1-receptors and inhibits histamine-stimulated vascular permeability in the conjunctiva. As a result, emedastine relieves the ocular pruritus associated with allergic conjunctivitis. The drug appears to exert no effects on adrenergic, dopaminergic, or serotonergic receptors.
Emedastine is administered topically to the eye. In oral administration studies of emedastine, it was shown that approximately 44% of the oral dose is excreted in the urine over 24 hours with only 3.6% of the dose excreted as parent drug. Two primary metabolites, 5- and 6-hydroxyemedastine, are excreted in the urine as both free and conjugated forms. The 5'-oxoanalogs of 5- and 6-hydroxyemedastine and the N-oxide are also formed as minor metabolites. The plasma elimination half-life is approximately 3-4 hours.
Following ocular administration of emedastine, there appears to be low systemic exposure; plasma concentrations were generally below the level of detection of the assay (< 0.3 ng/mL).