Oculastin (Azelastine Hydrochloride)

• Oculastin, an ocular antihistamine, acts on the histamine‑mediated allergic pathway of the eye.
• Allergic conjunctivitis: reduces ocular itching, redness, and swelling associated with allergic eye inflammation.
• Seasonal allergic conjunctivitis: provides rapid relief of symptoms triggered by seasonal allergens.
• Perennial allergic conjunctivitis: helps control chronic eye allergy symptoms throughout the year.

• Azelastine hydrochloride selectively blocks histamine H1 receptors on conjunctival and corneal cells, preventing histamine binding and subsequent mast‑cell degranulation. By stabilizing mast cells, it reduces the release of inflammatory mediators such as leukotrienes and cytokines, thereby diminishing vascular permeability, edema, and the sensory nerve activation that cause ocular itching and redness. The inhibition of these pathways also limits secondary recruitment of eosinophils and other immune cells, contributing to overall symptom control.

Azelastine eye drops may cause local and systemic adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Eye irritation or burning
• Stinging sensation upon instillation
• Transient blurred vision
• Dry eye sensation

Serious or Rare Side Effects

• Severe allergic reaction (anaphylaxis)
• Persistent eyelid swelling
• Corneal ulcer or infection

Before using Oculastin, certain precautions should be observed to ensure safety and effectiveness.

• Avoid use in patients with known hypersensitivity to azelastine or any excipients: discontinue if reaction occurs.
• Do not use if the container is damaged, the solution is discolored, or the expiration date has passed: check packaging before each use.
• Consult a healthcare professional before administering to children or the elderly: dosage may need adjustment.
• Monitor for signs of ocular infection or worsening symptoms: seek medical advice if condition does not improve.
• Store below 25°C: keep in the original pack, protect from moisture and direct sunlight.

Ocular antihistamines can interact with other ophthalmic or systemic agents, influencing efficacy or safety.

Major Interactions (Avoid)

• Concurrent use with ophthalmic corticosteroids: may mask signs of infection, requiring close monitoring.
• Use with contact lens solutions containing preservatives: can increase ocular irritation and compromise lens tolerance.

Moderate Interactions (Monitor Closely)

• Co‑administration with other ocular antihistamines or mast‑cell stabilizers: may heighten local side effects such as burning.
• Systemic antihistamines or decongestants: may have additive sedative effects, though minimal with topical use.
• Anticholinergic eye drops: could affect tear production, potentially worsening dry eye symptoms.