Trizin0.24%

Trizin is an ophthalmic (eye) antihistamine solution. It is FDA-approved and established for a single, specific indication:

• Ocular itching due to allergic conjunctivitis — relief of eye itching caused by seasonal or perennial allergic conjunctivitis (e.g., itching triggered by pollen, dust, pet dander, or other airborne allergens).

This ophthalmic formulation of Trizin is intended only for the eyes and is distinct from oral cetirizine tablets/syrups, which are used for systemic allergic conditions such as allergic rhinitis or urticaria. Trizin is not indicated for, and does not treat, infectious (bacterial or viral) conjunctivitis, dry eye disease, or glaucoma.

Each mL of Cetirizine Hydrochloride [Ophthalmic] ophthalmic solution contains cetirizine hydrochloride 2.4 mg (0.24% w/v) as the active ingredient, formulated as a sterile topical ophthalmic solution. Inactive ingredients typically include a preservative (commonly benzalkonium chloride in multi-dose bottles), tonicity agents, and pH-adjusting agents; preservative-free single-use containers are also available in some markets.

Trizin is a second-generation, selective histamine H1-receptor antagonist formulated specifically as a topical ophthalmic solution rather than for oral use. While oral cetirizine is widely used for systemic allergic symptoms, the ophthalmic formulation delivers the antihistamine directly to the ocular surface, providing targeted relief of allergic eye itching with minimal systemic absorption.

Trizin is supplied as a clear, sterile eye drop solution and is intended strictly for topical ophthalmic administration.

Trizin belongs to the ophthalmic anti-allergic / topical antihistamine therapeutic class, specifically the second-generation H1-antihistamines adapted for ocular use.

Mechanism of action: Cetirizine Hydrochloride [Ophthalmic] acts as a selective antagonist at histamine H1 receptors located on conjunctival nerve endings and vascular tissue. By blocking histamine binding at these receptors, it reduces the itching sensation and vasodilation that occur during an allergic reaction on the ocular surface.

Pharmacokinetics: Following topical ocular administration, systemic absorption of Cetirizine Hydrochloride [Ophthalmic] is minimal compared with oral cetirizine, which limits systemic antihistaminic effects (such as sedation) at recommended ophthalmic doses. Onset of itch relief has been demonstrated within minutes of instillation in clinical trials, with effect maintained through a twice-daily dosing interval.

Trizin is for topical ophthalmic (eye) use only — it must never be taken orally or injected. Instill directly into the conjunctival sac of the affected eye(s) using proper hand hygiene and sterile technique, taking care not to touch the dropper tip to any surface. See Dosage and Administration for full technique.

No clinically significant drug-drug interactions have been established for Trizin ophthalmic solution, reflecting its minimal systemic absorption when used as directed. However, the following precautions apply:

• Other topical eye medications: If more than one ophthalmic product is being used, separate administration of Trizin from other eye drops by at least 5–10 minutes to prevent one product washing out another.
• Contact lens care solutions/products: Concurrent use is not an interaction in the pharmacologic sense but may affect lens tolerance — see Precautions and Warnings regarding contact lens removal.

Always inform your physician or pharmacist about all other eye drops or medications in use.

Trizin is generally well tolerated. The most commonly reported adverse reactions (occurring in approximately 1–7% of patients in clinical trials) include:

• Ocular hyperemia (redness of the eye)
• Instillation-site pain or discomfort (mild transient stinging or burning upon administration)
• Reduced visual acuity (transient blurring)

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

Pregnancy: There are no adequate and well-controlled studies of Trizin in pregnant women. Animal reproduction studies with cetirizine have not shown evidence of harm to the fetus at doses far exceeding the recommended ophthalmic dose; however, Trizin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult a physician before use if pregnant or planning pregnancy.

Lactation: Cetirizine is known to be excreted in human breast milk after oral administration. Because systemic absorption from ophthalmic Trizin is expected to be substantially lower than from oral cetirizine, risk to a breastfeeding infant is likely minimal, but is not established with certainty. A nursing mother should consult her physician before using Trizin, weighing the benefit of treatment against any potential risk to the infant.

• For topical ophthalmic use only: Trizin must not be swallowed or injected.
• Avoid contamination: Do not touch the dropper tip to the eye, eyelid, fingers, or any other surface, to avoid contaminating the solution and injuring the eye.
• Contact lenses: Remove contact lenses before instilling Trizin, especially if the eye is red. Lenses may be reinserted approximately 10 minutes after administration, per product labeling, once instructed conditions are met (e.g., resolution of redness). This ophthalmic solution (multi-dose formulations) may contain benzalkonium chloride, which can be absorbed by soft contact lenses.
• Not for infectious conjunctivitis: Trizin treats allergic itching only. It is not a substitute for appropriate treatment of infectious (bacterial or viral) conjunctivitis ("pink eye"); using it alone for an infection may delay proper treatment. Consult a physician if there is significant redness, discharge, or suspicion of infection.
• Discard single-use containers after one use; do not reuse or store opened single-use containers for later application.
• If symptoms worsen, do not improve, or new symptoms (such as eye pain, vision changes, or persistent redness) develop, discontinue use and consult a physician promptly.

Specific data on overdose with Trizin ophthalmic solution are limited, given its formulation for topical ocular use and minimal systemic absorption. If a significantly larger amount than prescribed is instilled, or if the solution is accidentally swallowed, seek immediate medical attention or contact a poison control center / emergency services. Do not attempt unsupervised home treatment for a suspected overdose or accidental ingestion.

Store Trizin at controlled room temperature, approximately 15–25°C (59–77°F). Do not freeze. Keep single-use containers in their original foil pouch until ready to use, and discard after a single use. Keep the bottle tightly closed when not in use. Keep out of reach and sight of children.

• Pediatric use: Safety and effectiveness of Trizin have been established in children 2 years of age and older, at the same dosage as adults. Safety and effectiveness in children below 2 years of age have not been established.
• Geriatric use: No overall differences in safety or effectiveness have been observed between elderly and younger adult patients; no dose adjustment is required based on age alone.
• Renal/hepatic impairment: No specific dose adjustment guidance is established for Trizin ophthalmic solution, consistent with its minimal systemic absorption via the topical ocular route; use with the usual physician guidance.

Trizin is typically used for as long as allergic eye itching symptoms persist or during periods of known allergen exposure (e.g., a pollen season), as directed by a physician. There is no fixed maximum duration established in the label; however, if symptoms do not improve within a few days, worsen, or recur frequently, a physician should be consulted to reassess the diagnosis and treatment plan.

Cetirizine Hydrochloride [Ophthalmic] is classified under: Antihistamines (systemic class); Ophthalmic anti-allergic agents / topical ocular antihistamines (formulation-specific class). It is a second-generation H1-receptor antagonist adapted for topical ophthalmic delivery.

Cetirizine Hydrochloride [Ophthalmic] works by selectively blocking histamine H1 receptors on the ocular surface and conjunctival tissue. Histamine released during an allergic reaction binds these receptors to trigger itching, redness, and swelling; by occupying and blocking the receptor, Cetirizine Hydrochloride [Ophthalmic] prevents histamine from producing these effects, thereby relieving allergic eye itching.

Trizin is approved for use in children aged 2 years and older, at the same dose used in adults (one drop in each affected eye, twice daily). Safety and efficacy have not been established in children younger than 2 years of age, and Trizin should not be used in this age group without specific physician guidance. Parents/caregivers should supervise administration in children to ensure correct technique and to avoid contamination of the dropper tip or accidental ingestion of the bottle's contents.