Generic Name

Latanoprost

Mechanism

Latanoprost is a prostaglandin F₂α analogue that lowers intraocular pressure (IOP) by ↑ outflow of aqueous humor through the trabecular meshwork and uveoscleral pathway. It is converted in the eye to its active acid form, stimulating fibroblast‑like cells to remodel extracellular matrix, enhancing uveoscleral drainage while reducing trabecular resistance.

Pharmacokinetics

• Absorption: Rapid, predominantly ocular surface; minimal systemic absorption.
• Distribution: Latanoprost acid concentrates in the ciliary muscle, episcleral tissues.
• Metabolism: Hydrolyzed in ocular tissues; hepatic metabolism negligible for dosing.
• Elimination: Excreted via tears (unabsorbed) and small systemic amounts through renal/urinary routes.
• Onset of action: 18–24 h after first dose, reaches steady‑state in ~1 month.
• Half‑life: ~8–10 h intraocularly; systemic plasma half‑life ~30 min.

Indications

• Primary open‑angle glaucoma (POAG)
• Ocular hypertension (OHT)
• Prophylactic use in patients at risk of steroid‑induced IOP rise or post‑surgical ocular hypertension.

Contraindications

• Contraindicated in patients with known hypersensitivity to latanoprost, prostaglandins, or any formulation component.
• Caution in patients with active ocular inflammation or infections (e.g., infectious conjunctivitis).
• Not studied in pregnancy; use only if benefit outweighs risk.
• Avoid use in patients with ocular surface disease severe enough to impair tear film clearance.

Dosing

• Dose: 0.005 % (5 µg/mL) solution.
• Schedule: Apply one drop in the affected eye once daily in the evening; 1–2 min wait before bedtime and sleep to maintain drop wetting.
• Pre‑treatment counseling: Wash hands, avoid touching eye, administer before sleep to maximize absorption.
• Switching considerations: If transitioning from another prostaglandin analogue, observe a 1‑week washout to avoid additive pigmentation effects.

Adverse Effects

• Common:
• Conjunctival hyperemia
• Periorbital brown‑brown or gray staining of eyelash and eyelid skin
• Mild itching or burning
• Dry eye symptoms (rare)
• Serious:
• Allergic contact dermatitis (rash, edema)
• Ocular surface irritation leading to discontinuation
• Rare increases in corneal vascularization
• Iris pigment dispersion in susceptible patients (rare)

Monitoring

• IOP: baseline, 1–2 weeks, and every 4–6 weeks until stable.
• Eyelid & periorbital pigmentation: assess at each visit; educate about expected changes.
• Ocular surface integrity: regular slit‑lamp exam to monitor hyperemia or inflammation.
• Corneal health: evaluate for any pigment dispersion or vascular changes.

Clinical Pearls

• Optimal timing: Evening dosing reduces peak intraocular pressure during the night‑time rise; improves patient compliance with fewer morning awakenings.
• Withdrawal “wash‑out”: A 1‑week washout before switching to another prostaglandin reduces additive iris pigmentation and potential over‑stimulation of the uveoscleral outflow pathway.
• Eyelid staining is benign: Brown/gray eyelid/tarsal pigment deposition is harmless; reassure patients and counsel against topical skin cleansers that might intensify staining.
• Adjunctive therapy: Latanoprost can be effectively combined with selective β‑blockers or α‑agonists; consider fixed‑dose combination drops for improved adherence.
• Pregnancy & lactation: No evidence of systemic exposure; topical only, but minimal precautionary use recommended; discuss with patient.

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• *All information is current as of 2024; clinicians should consult the latest prescribing information and peer‑reviewed literature before making therapeutic decisions.*