Generic Name

Xalatan

Mechanism

• Prostaglandin analogue that mimics endogenous prostaglandin F2α.
• Binds to latrophilin receptor on ciliary body cells → stimulates matrix metalloproteinases.
• Increases uveoscleral outflow by remodeling extracellular matrix.
• Net result: significant reduction in intra‑ocular pressure (~30–40%).

Pharmacokinetics

• Topical ocular formulation (0.005% solution).
• Rapidly absorbed through the conjunctiva; peak corneal concentration occurs within 1–2 hours.
• Minimal systemic absorption (<2% of applied dose).
• Metabolized in ocular tissues; no clinically relevant metabolites.
• Half‑life at ocular site ≈ 10–12 hours; steady‑state achieved after 4–6 weeks of therapy.

Indications

• Open‑angle glaucoma.
• Ocular hypertension associated with angle‑closure or normal‑tension glaucoma.
• Precautionary use in patients with pseudophakic or aphakic eyes to prevent pressure rise.

Contraindications

• Contraindicated in:
• Active ocular infection (e.g., viral keratitis, corneal ulcer).
• Herpes zoster ophthalmicus within the last 4 weeks.
• Hypersensitivity to latanoprost or excipients.
• Warning: Patients on steroid‑responsive glaucoma or those anticipated to need steroids may have uncontrolled IOP if latanoprost is discontinued abruptly.

Dosing

• Standard dose: 1–2 drops in the affected eye(s) once daily (preferably evening).
• Administration:
• Shake vial gently before use.
• Clean external eye with sterile wipes (avoid touching the dropper tip).
• Apply a drop, then gently close the eye for 1–2 minutes.
• Discontinue 8–12 hours before any ocular surgery to avoid elevated pressure.

Adverse Effects

• Common:
• Redness, itching, mild irritation.
• Hyperemia (conjunctival redness), blepharitis.
• Altered iris pigmentation (brown).
• Slow discomfort at the eyelid or lashes.
• Serious:
• Hypopyon glaucoma: posterior segment inflammation, may require systemic steroids.
• Vision loss due to pigmentary changes in the iris.
• Allergic reaction (rare) leading to blepharitis and ocular surface inflammation.
• Heterochromia (change in iris color).
• Note: Report any ocular pain, vision changes, or decreased visual acuity promptly.

Monitoring

• Intra‑ocular pressure (IOP): baseline, 4–6 weeks, monthly thereafter until stable.
• Ocular surface exam: evaluate for redness, blepharitis, eyelash growth.
• Contact lens wearers: monitor for keratitis or lens intolerance.
• Follow‑up: at least every 3–6 months for chronic therapy.

Clinical Pearls

• Timing of administration: Evening dosing yields better IOP control as the peak effect occurs at night.
• Adding a preservative‑free formulation reduces ocular surface irritation particularly in patients on multiple topical agents.
• Bilateral therapy: While often prescribed monotherapy, using both eyes leads to faster IOP reduction when both eyes are affected.
• Avoid mixing with benzalkonium chloride–containing drops to prevent additive ocular surface toxicity; use only preservative‑free products.
• Stopping abruptly can precipitate rebound IOP elevation; counsel patients to resume at least one day after discontinuation.
• Patient counseling: advise patients to report any change in eye color or vision, especially in those with darker irides.
• Drug‑drug interactions: no known interactions, but caution in patients using topical steroids to avoid misattributing IOP changes.

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• Xalatan remains a cornerstone in glaucoma therapy due to its efficacy, once‑daily convenience, and favorable ocular safety profile. Proper patient education and regular monitoring are essential to maximize therapeutic benefit and mitigate risks.