Xalatan

Xalatan

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.