A fixed-dose ophthalmic solution combining a sympathomimetic alpha-adrenergic agonist (Naphazoline) with a first-generation alkylamine antihistamine (Chlorpheniramine Maleate). This combination provides rapid symptomatic relief from ocular itching and redness associated with allergic conjunctivitis by inducing vasoconstriction and blocking histamine H1 receptors. It is a mainstay for acute, short-term management of allergic eye conditions in the Indian market.
Adult: One to two drops instilled into the affected eye(s) every 3 to 4 hours, or as needed. Do not exceed 4 doses (8 drops) per eye per day.
Note: 1. Wash hands before use. 2. Tilt head back, pull lower eyelid down to form a pouch. 3. Instill the prescribed number of drops without touching the dropper tip to eye, eyelid, or any surface. 4. Close eyes gently and apply gentle pressure to the inner corner of the eye (nasolacrimal occlusion) for 1-2 minutes to minimize systemic absorption. 5. Do not use while wearing soft contact lenses; wait at least 15 minutes after instillation before reinserting lenses.
The combination works synergistically. Naphazoline acts on alpha-1 adrenergic receptors on the conjunctival vasculature, causing vasoconstriction, which reduces redness and edema. Chlorpheniramine competitively antagonizes histamine at the H1 receptors on conjunctival blood vessels and sensory nerve endings, inhibiting the vasodilation, increased vascular permeability, and itching mediated by histamine release.
Pregnancy: Category C: Animal reproduction studies have not been conducted. Use only if potential benefit justifies potential risk to the fetus. Systemic absorption can occur. Avoid, especially in the first trimester.
Driving: May cause transient blurred vision, dizziness, or drowsiness. Patients should not drive or operate machinery until their vision is clear and they are sure they are not affected.
| Monoamine Oxidase Inhibitors (MAOIs) - e.g., Phenelzine, Tranylcypromine | Potentiation of pressor effects of Naphazoline, risk of severe hypertension. | Major |
| Tricyclic Antidepressants (TCAs) - e.g., Amitriptyline | Increased anticholinergic effects (dry eyes, urinary retention) and potentiation of pressor effects. | Moderate |
| Beta-blockers (Topical Ophthalmic) - e.g., Timolol | Potential additive effect on reducing intraocular pressure; may mask symptoms of angle-closure glaucoma. | Moderate |
| Other CNS Depressants (Alcohol, Benzodiazepines, Opioids) | Additive sedation with systemic absorption of Chlorpheniramine. | Moderate |
| Antihypertensives | Naphazoline may counteract the hypotensive effect due to vasoconstriction. | Moderate |