Alcaftadine

Approved Indications:

• Seasonal Allergic Conjunctivitis (SAC)
  Indicated for the prevention of itching associated with allergic conjunctivitis in adults and children 2 years of age and older.

Clinically Accepted Off-Label Use:

• Perennial Allergic Conjunctivitis (PAC)
  Though not FDA-approved for PAC, it is sometimes used in practice for chronic, non-seasonal allergic ocular symptoms.

Use Scope by Severity:

• Recommended for mild to moderate allergic conjunctivitis symptoms, especially where ocular itching is predominant.

Adults and Children (≥2 years):

• Dosage: Instill 1 drop of Alcaftadine 0.25% ophthalmic solution in each affected eye once daily.
• Route: Ophthalmic (topical to the eye)
• Frequency: Once daily
• Duration: Use during allergen exposure season or as directed by a physician.

Pediatric Use (<2 years):

• Not recommended — safety and efficacy have not been established.

Geriatric Use:

• No specific dose adjustment required; clinical trials show similar safety and efficacy as in younger adults.

Special Populations:

• Renal Impairment: No dose adjustment needed.
• Hepatic Impairment: No dose adjustment needed.
• Minimal systemic absorption makes dose adjustments unnecessary.

Administration Advice:

• Remove contact lenses prior to use. Wait at least 10 minutes before reinserting.
• If using other ophthalmic medications, allow at least 5 minutes between applications.
• Avoid touching the dropper tip to any surface, including the eye.

Alcaftadine is a tricyclic antihistamine that acts as a selective antagonist at histamine H₁, H₂, and H₄ receptors. Its primary action is H₁ receptor blockade, preventing histamine-induced itching in the conjunctiva. It also exhibits mast cell stabilization, inhibiting the release of inflammatory mediators including histamine, prostaglandins, and cytokines. Through dual inhibition—blocking histamine receptors and preventing mast cell degranulation—Alcaftadine reduces ocular allergy symptoms such as itching, redness, and inflammation.

• Absorption: Low systemic absorption after topical administration to the eye.
• Bioavailability: Minimal; therapeutic effect is localized.
• Onset of Action: Within 3 to 15 minutes post-instillation.
• Time to Peak Effect: Within 3 hours.
• Metabolism: Rapid hepatic metabolism to an active carboxylic acid metabolite.
• Half-Life: Approximately 2 hours for the parent drug.
• Excretion: Primarily via urine as inactive metabolites.
• Systemic Exposure: Negligible; limits potential for systemic adverse effects.

Pregnancy:

• FDA Pregnancy Category: Not assigned (per current FDA PLLR guidelines).
• Risk Summary: No adequate human data; animal studies have shown no fetal harm at therapeutic doses. Use during pregnancy only if clearly needed.

Lactation:

• Unknown whether Alcaftadine or its metabolites are excreted in human breast milk.
• Systemic exposure is low; however, caution is advised when used during breastfeeding.

Clinical Note: Because systemic absorption is minimal, the potential for fetal or infant exposure is low, but clinical discretion is advised.

• Primary Class: Ophthalmic Antihistamine
• Subclass: Dual-acting agent (H₁ antagonist + mast cell stabilizer)
• Pharmacologic Class: Tricyclic antihistamine (topical use)

• Hypersensitivity to Alcaftadine or any component of the formulation.
• Active ocular infections (may mask symptoms or delay healing).
• Use in children under 2 years of age.

• Contact Lens Use: Remove lenses before instillation; wait ≥10 minutes before reinsertion.
• Ocular Irritation: Discontinue if irritation, burning, or worsening symptoms occur.
• Systemic Hypersensitivity: Though rare, discontinue if allergic reactions (e.g., swelling, rash) occur.
• Sterility Maintenance: Avoid touching the dropper tip to any surface or eye.
• Use Limitation: Not intended for treating eye infections or other non-allergic conditions.

Common Adverse Effects (≥1%):

• Eye irritation or stinging
• Nasopharyngitis
• Headache
• Eye redness
• Dry eye sensation

Uncommon (<1%):

• Conjunctival hyperemia
• Blurred vision
• Eye discharge
• Eyelid edema

Rare but Serious:

• Hypersensitivity reactions (e.g., angioedema, anaphylaxis — extremely rare)

Dose-Dependency & Onset:

• Symptoms typically occur within minutes of instillation and are usually transient.
• Side effects are not significantly dose-dependent due to once-daily topical administration.

• Drug-Drug: No significant systemic interactions due to low systemic absorption.
• Drug-Food: Not applicable.
• Drug-Alcohol: No known interaction.
• Enzyme System: Does not significantly interact with CYP450 enzymes.

Concurrent Ophthalmic Medications:

• Separate administration by at least 5 minutes if using other eye drops.

Preservative Warning:

• Contains benzalkonium chloride, which can discolor soft contact lenses. Remove lenses before use.

• Indications and Dosage: No changes in approved uses or dosing in recent years.
• Regulatory Status: Continues to be approved by FDA, EMA, and other authorities for allergic conjunctivitis.
• Clinical Guidelines: Reaffirmed in current allergy and ophthalmology guidelines as a first-line topical treatment.
• Safety Profile: No new black box warnings or contraindications reported.

• Temperature: Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C to 30°C.
• Humidity: Store in a dry place.
• Light: Protect from light. Keep container tightly closed.
• Freezing: Do not freeze.
• Special Handling:
• Keep bottle capped tightly when not in use.
• Avoid contamination by preventing dropper contact with surfaces.