Alcadin0.25%

Alcadin ophthalmic solution is indicated for the following use:

Established / FDA-approved use

• Prevention of itching associated with allergic conjunctivitis (allergic eye itching triggered by pollen, dust, animal dander, and other airborne allergens). This is the sole approved indication for Alcadin.

Alcadin is a topical, once-daily eye drop intended for prophylactic (preventive) relief of ocular itching rather than treatment of an already-established severe allergic flare. It is not indicated for infective (bacterial or viral) conjunctivitis, dry eye disease, or irritation related to contact lens wear.

Each mL of Alcaftadine ophthalmic solution contains Alcaftadine 2.5 mg (0.25% w/v) as the active ingredient, formulated as a sterile, isotonic, topical ophthalmic solution preserved with benzalkonium chloride.

Alcadin is a topical ophthalmic antihistamine with additional mast cell-stabilizing activity, developed specifically for the prevention of itching caused by allergic conjunctivitis. It is formulated as a sterile ophthalmic solution instilled directly into the eye once daily.

Alcadin works locally at the ocular surface with minimal systemic absorption, giving it a favorable local tolerability profile and a convenient once-daily dosing schedule compared with older multi-dose-per-day antihistamine eye drops.

Alcaftadine is a selective histamine H1-receptor antagonist that also binds H2 and H4 receptors and possesses mast cell-stabilizing properties, giving it a dual mechanism of action against ocular allergic itching.

• H1-receptor antagonism: blocks histamine from binding to H1 receptors on conjunctival nerve endings and vasculature, directly reducing itching and vasodilation (redness).
• Mast cell stabilization: inhibits degranulation of conjunctival mast cells, reducing further release of histamine and other inflammatory mediators.
• Additional effects: inhibits eosinophil chemotaxis and up-regulation of intercellular adhesion molecule-1 (ICAM-1), which may reduce downstream allergic inflammatory recruitment.

Following ocular instillation, systemic absorption of Alcaftadine is low, and the drug and its active metabolite are cleared primarily via hepatic metabolism and renal/fecal excretion.

Alcadin is for topical ophthalmic use only — it must never be injected or taken by mouth.

• Instill one drop into the conjunctival sac of each affected eye.
• Avoid touching the dropper tip to the eye or any surface to prevent contamination of the solution.
• If contact lenses are worn, remove them before instilling Alcadin and wait at least 10 minutes before reinserting, since the preservative (benzalkonium chloride) can be absorbed by soft contact lenses.
• Do not use Alcadin to treat contact lens-related eye irritation.

No clinically significant drug-drug interactions have been established for Alcadin, largely because of its low systemic absorption after topical ocular administration.

• Other ophthalmic medications: if more than one topical eye medication is being used, separate administration by at least 5–10 minutes to prevent one drop from washing out another.
• Contact lens care solutions/products: no specific pharmacologic interaction, but see Precautions regarding contact lens removal.

No formal systemic drug interaction studies have been conducted with Alcadin; patients should inform their physician or pharmacist of all other medicines and eye drops they use.

Alcadin is generally well tolerated. Reported adverse effects include:

Common ocular effects (each reported in a small percentage of users)

• Eye irritation
• Burning or stinging sensation upon instillation
• Eye redness
• Eye itching (paradoxical, uncommon)

Less common systemic effects

• Headache
• Nasopharyngitis (cold-like symptoms)
• Influenza-like symptoms

These effects are typically mild and transient. Patients should contact their physician if irritation is severe, persistent, or accompanied by vision changes, significant pain, or discharge.

Pregnancy: Animal reproduction studies with Alcadin have not shown evidence of fetal harm; however, adequate and well-controlled studies in pregnant women are lacking. Because ocular administration results in low systemic absorption, systemic fetal exposure is expected to be minimal, but Alcadin should be used during pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus. Consult a physician before use.

Lactation: It is not known whether Alcadin is excreted in human breast milk. Caution should be exercised, and a physician should be consulted, when considering Alcadin in a breastfeeding mother.

• Contact lens wearers: remove contact lenses before instilling Alcadin and wait at least 10 minutes before reinsertion; the preservative benzalkonium chloride may be absorbed by soft contact lenses. Alcadin is not indicated to treat contact lens-related irritation.
• Topical use only: for use in the eye only; not for injection or oral use.
• Avoid contamination: do not touch the dropper tip to the eye, eyelid, fingers, or any surface.
• Not for infective conjunctivitis: Alcadin treats allergic itching, not bacterial or viral eye infections; seek medical advice if discharge, significant pain, or vision changes occur.
• Discontinue and consult a physician if eye irritation worsens or persists beyond expected use.

Ocular overdose (e.g., accidental instillation of multiple drops) is unlikely to cause serious harm given the low systemic absorption of Alcadin, but excess drops should be flushed from the eye with lukewarm water.

If Alcadin is accidentally swallowed, seek immediate medical attention or contact a poison control center / emergency services rather than attempting home treatment. Do not induce vomiting unless specifically advised by a medical professional.

Store Alcadin ophthalmic solution at room temperature, between 15-25°C (59-77°F), away from direct light and moisture. Keep the bottle tightly closed when not in use and discard any remaining solution 4 weeks after first opening, or per the expiry date on the label, whichever is sooner. Keep out of reach of children.

Pediatric use

Alcadin is approved for children 2 years of age and older at the same dose as adults. Safety and efficacy have not been established in children under 2 years of age.

Geriatric use

No overall differences in safety or effectiveness of Alcadin have been observed between elderly and younger adult patients; no dose adjustment is required.

Renal and hepatic impairment

No dedicated studies have been conducted; given the low systemic absorption after ocular use, no dose adjustment is generally considered necessary, but caution and physician guidance is advised.

Alcadin may be used once daily for as long as allergen exposure and associated itching symptoms persist (e.g., throughout a pollen season), based on a physician's guidance. There is no defined maximum duration in the label, but patients should have periodic follow-up if using it for prolonged, continuous periods.

Ophthalmic antihistamine; H1-receptor antagonist; mast cell stabilizer (anti-allergic ophthalmic agent).

Alcaftadine works by selectively blocking histamine H1 receptors on the conjunctival surface (preventing histamine-induced itching and redness) while also stabilizing mast cells to reduce further release of histamine and inflammatory mediators, giving it a dual anti-allergic mechanism at the site of application.

B

Alcadin is approved for use in children 2 years of age and older, at the same dosage as adults (one drop in each affected eye once daily). Safety and efficacy of Alcadin have not been established in infants and children below 2 years of age, and it should not be used in this age group outside of physician guidance.