latanoprost

Latanoprost is a prostaglandin F2α analogue used in the treatment of open-angle glaucoma and ocular hypertension. It lowers intraocular pressure by increasing the drainage of aqueous humor through the uveoscleral pathway. It is administered as an ophthalmic solution, typically one drop in the affected eye once daily, usually in the evening.

Pharmacology and pharmacokinetics: Latanoprost is a prodrug that is hydrolyzed in the cornea to latanoprost acid, the active form. The IOP-lowering effect begins within 3-4 hours and commonly reaches its maximum within 8-12 hours, with the effect lasting about 24 hours. Adherence to once-daily dosing is encouraged, and missed doses should be resumed rather than doubled.

Adverse effects and precautions: Common adverse effects include conjunctival hyperemia, eyelash growth or thickening, periorbital skin darkening, conjunctival irritation, and dry eye. Less common but more serious risks include intraocular inflammation or macular edema, particularly after eye surgery. Latanoprost can cause irreversible iris pigmentation increase (browning) with long-term use. It should be used with caution in active intraocular inflammation and in people with known allergy to prostaglandins.

Contraindications and interactions: Contraindicated in hypersensitivity to latanoprost or its components. The preservative benzalkonium chloride in some formulations can affect contact lenses; lenses should be removed before administration and reinserted after about 15 minutes. There are no major systemic drug interactions, but concurrent use with other ocular hypotensives may have additive effects.

Storage and availability: Brand name Xalatan; generic latanoprost is widely available. Before opening, refrigerate at 2-8°C. After first use, store at room temperature, protect from light, and discard after the period specified by the manufacturer (commonly around 6 weeks).