Epinastine hydrochloride

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# Overview
Epinastine hydrochloride is a H1 histamine receptor antagonist that is FDA approved for the prophylaxis of itching associated with allergic conjunctivitis.   Common adverse reactions include burning sensation in the eye, folliculosis, hyperemia, and pruritus, infection.

# Adult Indications and Dosage

## FDA-Labeled Indications and Dosage (Adult)

# Indications
- Epinastine hydrochloride ophthalmic solution is indicated for the prevention of itching associated with allergic conjunctivitis.

# Dosage
- The recommended dosage is one drop in each eye twice a day.
- Treatment should be continued throughout the period of exposure (i.e., until the pollen season is over or until exposure to the offending allergen is terminated), even when symptoms are absent.

# DOSAGE FORMS AND STRENGTHS
- Solution containing 0.5 mg/mL epinastine hydrochloride

## Off-Label Use and Dosage (Adult)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Epinastine hydrochloride in adult patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Epinastine hydrochloride in adult patients.

# Pediatric Indications and Dosage

## FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Epinastine hydrochloride in pediatric patients.

## Off-Label Use and Dosage (Pediatric)

### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Epinastine hydrochloride in pediatric patients.

### NonGuideline-Supported Use
There is limited information regarding Off-Label NonGuideline-Supported Use of Epinastine hydrochloride in pediatric patients.

# Contraindications
- None

# Warnings
Contamination of Tip and Solution
- Patients should be instructed to avoid allowing the tip of the dispensing container to contact the eye, surrounding structures, fingers, or any other surface in order to avoid contamination of the solution by common bacteria known to cause ocular infections. Serious damage to the eye and subsequent loss of vision may result from using contaminated solutions.
- Bottle should be kept tightly closed when not in use.
Use with Contact Lenses
- Patients should be advised not to wear a contact lens if their eye is red. Epinastine hydrochloride ophthalmic solution should not be used to treat contact lens-related irritation.
- The preservative in epinastine hydrochloride, benzalkonium chloride, may be absorbed by soft contact lenses. Contact lenses should be removed prior to instillation of epinastine hydrochloride ophthalmic solution and may be reinserted after 10 minutes following its administration.
Topical Ophthalmic Use Only
- Epinastine hydrochloride is for topical ophthalmic use only and not for injection or oral use.

# Adverse Reactions

## Clinical Trials Experience
- Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.
- The most frequently reported ocular adverse reactions occurring in approximately 1 to 10% of patients were burning sensation in the eye, folliculosis, hyperemia, and pruritus.
- The most frequently reported non-ocular adverse reactions were infection (cold symptoms and upper respiratory infections), seen in approximately 10% of patients, and headache, rhinitis, sinusitis, increased cough, and pharyngitis, seen in approximately 1 to 3% of patients.
- Some of these reactions were similar to the underlying disease being studied.

## Postmarketing Experience
- The following reactions have been identified during postmarketing use of epinastine hydrochloride in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. The reactions, which have been chosen for inclusion due to either their seriousness, frequency of reporting, possible causal connection to epinastine hydrochloride, or a combination of these factors, include: lacrimation increased.

# Drug Interactions
There is limited information regarding Epinastine hydrochloride Drug Interactions in the drug label.

# Use in Specific Populations

### Pregnancy
Pregnancy Category (FDA): 
Teratogenic Effects
Pregnancy Category C
- In an embryofetal developmental study in pregnant rats, maternal toxicity with no embryofetal effects was observed at an oral dose that was approximately 150,000 times the maximum recommended ocular human dose (MROHD) of 0.0014 mg/kg/day on a mg/kg basis. Total resorptions and abortion were observed in an embryofetal study in pregnant rabbits at an oral dose that was approximately 55,000 times the MROHD. In both studies, no drug-induced teratogenic effects were noted.
- Epinastine reduced pup body weight gain following an oral dose to pregnant rats that was approximately 90,000 times the MROHD.
- There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, epinastine hydrochloride ophthalmic solution should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Pregnancy Category (AUS):
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Epinastine hydrochloride in women who are pregnant.

### Labor and Delivery
There is no FDA guidance on use of Epinastine hydrochloride during labor and delivery.

### Nursing Mothers
- A study in lactating rats revealed excretion of epinastine in the breast milk. It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when epinastine hydrochloride ophthalmic solution is administered to a nursing woman.

### Pediatric Use
- Safety and effectiveness in pediatric patients below the age of 2 years have not been established.

### Geriatic Use
- No overall differences in safety or effectiveness have been observed between elderly and younger patients.

### Gender
There is no FDA guidance on the use of Epinastine hydrochloride with respect to specific gender populations.

### Race
There is no FDA guidance on the use of Epinastine hydrochloride with respect to specific racial populations.

### Renal Impairment
There is no FDA guidance on the use of Epinastine hydrochloride in patients with renal impairment.

### Hepatic Impairment
There is no FDA guidance on the use of Epinastine hydrochloride in patients with hepatic impairment.

### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Epinastine hydrochloride in women of reproductive potentials and males.

### Immunocompromised Patients
There is no FDA guidance one the use of Epinastine hydrochloride in patients who are immunocompromised.

# Administration and Monitoring

### Administration
- Topical

### Monitoring
There is limited information regarding Monitoring of Epinastine hydrochloride in the drug label.

# IV Compatibility
There is limited information regarding IV Compatibility of Epinastine hydrochloride in the drug label.

# Overdosage
There is limited information regarding Chronic Overdose of Epinastine hydrochloride in the drug label.

# Pharmacology

## Mechanism of Action
- Epinastine is a topically active, direct H1-receptor antagonist and an inhibitor of the release of histamine from the mast cell. Epinastine is selective for the histamine H1-receptor and has affinity for the histamine H2 receptor. Epinastine also possesses affinity for the 1,  2-, and 5-HT2receptors.

## Structure
- Epinastine Hydrochloride Ophthalmic Solution 0.05% is a clear, colorless, sterile isotonic solution containing epinastine hydrochloride, an antihistamine and an inhibitor of histamine release from the mast cell for topical administration to the eyes.
- Epinastine hydrochloride is represented by the following structural formula:
Chemical Name:
3-Amino-9,13b-dihydro-1H-dibenzimidazoazepine hydrochloride
Each mL contains: Active: Epinastine hydrochloride 0.05% (0.5 mg/mL) equivalent to epinastine 0.044% (0.44 mg/mL); Preservative: Benzalkonium chloride 0.01%; Inactives: Edetate disodium dihydrate; purified water; sodium chloride; sodium phosphate, monobasic; and sodium hydroxide and/or hydrochloric acid (to adjust pH). Epinastine Hydrochloride Ophthalmic Solution has a pH of approximately 7 and an osmolality range of 250 to 310 mOsm/kg.

## Pharmacodynamics
There is limited information regarding Pharmacodynamics of Epinastine hydrochloride in the drug label.

## Pharmacokinetics
- Fourteen subjects, with allergic conjunctivitis, received one drop of epinastine hydrochloride ophthalmic solution in each eye twice daily for 7 days. On day 7, average maximum epinastine plasma concentrations of 0.040.014 ng/ml were reached after about two hours indicating low systemic exposure. While these concentrations represented an increase over those seen following a single dose, the day 1 and day 7 Area Under the Curve (AUC) values were unchanged indicating that there is no increase in systemic absorption with multiple dosing. Epinastine is 64% bound to plasma proteins. The total systemic clearance is approximately 56 L/hr and the terminal plasma elimination half-life is about 12 hours. Epinastine is mainly excreted unchanged. About 55% of an intravenous dose is recovered unchanged in the urine with about 30% in feces. Less than 10% is metabolized. The renal elimination is mainly via active tubular secretion.

## Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment of Fertility
- In 18-month or 2-year dietary carcinogenicity studies in mice or rats, respectively, epinastine was not carcinogenic at doses up to 40 mg/kg . Epinastine in newly synthesized batches was negative for mutagenicity in the Ames/Salmonella assay and in vitro chromosome aberration assay using human lymphocytes. Positive results were seen with early batches of epinastine in two in vitro chromosomal aberration studies conducted in 1980s with human peripheral lymphocytes and with V79 cells, respectively. Epinastine was negative in the in vivo clastogenicity studies, including the mouse micronucleus assay and chromosome aberration assay in Chinese hamsters. Epinastine was also negative in the cell transformation assay using Syrian hamster embryo cells, V79/HGPRT mammalian cell point mutation assay, and in vivo/in vitro unscheduled DNA synthesis assay using rat primary hepatocytes. Epinastine had no effect on fertility of male rats. Decreased fertility in female rats was observed at an oral dose up to approximately 90,000 times the MROHD.

# Clinical Studies
- Epinastine hydrochloride 0.05% has been shown to be significantly superior to vehicle for improving ocular itching in patients with allergic conjunctivitis in clinical studies using two different models: (1) conjunctival antigen challenge (CAC) where patients were dosed and then received antigen instilled into the inferior conjunctival fornix; and (2) environmental field studies where patients were dosed and evaluated during allergy season in their natural habitat. Results demonstrated a rapid onset of action for epinastine hydrochloride 0.05% within 3 to 5 minutes after conjunctival antigen challenge. Duration of effect was shown to be 8 hours, making a twice daily regimen suitable. This dosing regimen was shown to be safe and effective for up to 8 weeks, without evidence of tachyphylaxis.

# How Supplied
- Epinastine Hydrochloride Ophthalmic Solution 0.05% is supplied sterile in opaque white LDPE plastic bottles with dropper tips and white opaque HDPE copolymer caps as follows:
- 5 mL in 11 mL bottle NDC 60505-0584-1

## Storage
- Storage: Store at 20 to 25C (68 to 77F) .
Keep bottle tightly closed and out of the reach of children.

# Images

## Drug Images

## Package and Label Display Panel

# Patient Counseling Information
Sterility of Dropper Tip
- Patients should be advised not to touch dropper tip to any surface, as this may contaminate the contents.
Concomitant Use of Contact Lenses
- Patients should be advised not to wear a contact lens if their eye is red. Patients should be advised that epinastine hydrochloride should not be used to treat contact lens-related irritation. Patients should also be advised to remove contact lenses prior to instillation of epinastine hydrochloride. The preservative in epinastine hydrochloride, benzalkonium chloride, may be absorbed by soft contact lenses. Lenses may be reinserted after 10 minutes following administration of epinastine hydrochloride.
Topical Ophthalmic Use Only
- For topical ophthalmic administration only.

# Precautions with Alcohol
- Alcohol-Epinastine hydrochloride interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

# Brand Names
- EPINASTINE HYDROCHLORIDE

# Look-Alike Drug Names
There is limited information regarding Epinastine hydrochloride Look-Alike Drug Names in the drug label.

# Drug Shortage Status

# Price