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Latanoprost (Xalatan)

One of the most widely prescribed glaucoma drops. A once-daily prostaglandin analog that lowers eye pressure with strong effect and minimal systemic side effects.

Drug Class: Prostaglandin Analog

7 min read

Latanoprost (brand name Xalatan) is one of the most widely prescribed glaucoma medications. It belongs to the prostaglandin analog class - a group that also includes travoprost, bimatoprost, and tafluprost - and provides one of the strongest single-drop intraocular pressure reductions available, with once-daily dosing and minimal systemic side effects. Since approval in 1996, it has become a first-line nightly drop for many patients with open-angle glaucoma or ocular hypertension.

Key Takeaways

  • Lowers eye pressure by 25-32% with once-daily evening dosing - among the most effective single-drop reductions available
  • Class side effects include gradual iris color darkening (often permanent), lengthening and darkening of eyelashes, and pigmentation of periocular skin
  • Generally well tolerated systemically - much less risk of cardiovascular and pulmonary effects than timolol
  • Available generically at low cost; fixed combinations include Rocklatan with netarsudil in the U.S. and Xalacom with timolol in some non-U.S. markets
  • Storage rules vary by product - branded Xalatan and many generics require refrigeration before opening (2-8°C / 36-46°F); once opened, most products may be kept at room temperature (up to 25°C / 77°F) for up to 6 weeks. Some generics are room-temperature stable throughout - always check the label on your specific bottle

How It Works

Latanoprost is a synthetic analog of prostaglandin F2α. It binds to FP prostaglandin receptors and increases the outflow of aqueous humor primarily through the uveoscleral pathway (the secondary, non-trabecular drainage route), with smaller effects on the trabecular meshwork. Increased outflow lowers eye pressure significantly without changing pupil size, accommodation, or aqueous production.

The effect:

  • Begins within 3-4 hours of dosing
  • Reaches peak at 8-12 hours
  • Lasts more than 24 hours, supporting once-daily dosing
  • Most of the pressure-lowering effect is established within 1-2 weeks; steady-state is reached by about 4 weeks

Common Uses

Combinations:

  • Rocklatan - latanoprost + netarsudil (adds rho-kinase inhibition; FDA-approved in the U.S.)
  • Xalacom - latanoprost + timolol (available in Europe and other markets; not FDA-approved in the U.S.)

A related single-molecule product, Vyzulta (latanoprostene bunod), is not a fixed combination but a nitric-oxide-donating prostaglandin that is hydrolyzed in the eye to latanoprost acid plus a nitric-oxide-releasing moiety.

How to Use

  • Dosing: One drop in affected eye(s) once daily, in the evening
  • Evening dosing matches the typical IOP rhythm and provides slightly better 24-hour control than morning dosing
  • Press on the inner corner of the eye for 1-2 minutes after instillation
  • Wait 5+ minutes between different eye drops
  • Remove contact lenses before use; reinsert after 15 minutes
  • Dosing more than once daily does not increase pressure lowering, and in some studies has produced less pressure reduction than once-daily dosing - stick to once nightly
  • Storage: Follow the label on your bottle. Branded Xalatan and many generic latanoprost products require refrigeration of the unopened bottle (2-8°C / 36-46°F); once opened, most products may be kept at room temperature for up to 6 weeks. Some generics are room-temperature stable throughout - always check your specific bottle

Side Effects

Local Effects

  • Mild conjunctival hyperemia - typically less than other prostaglandins; often improves over weeks
  • Eyelash growth - longer, thicker, darker lashes develop within 4-6 weeks; the change persists while the drop is used and partially reverses over months after stopping
  • Iris color darkening - slow change in patients with mixed-color irises (hazel, green-brown), over 6-12 months; usually permanent
  • Periocular and eyelid skin darkening - gradually develops with chronic use; usually fades partially or fully after stopping, but may not always reverse completely
  • Periocular fat atrophy (prostaglandin-associated periorbitopathy) - subtle hollowing of the upper eyelid sulcus; may improve after stopping or switching
  • Cystoid macular edema - uncommon; reported particularly in pseudophakic eyes with disrupted posterior capsule
  • Reactivation of herpes simplex keratitis in patients with prior history

Systemic Effects

  • Minimal - much less than timolol
  • Rare reports of muscle aches or upper respiratory symptoms
  • No significant impact on heart rate, blood pressure, or breathing in most patients

Precautions

Prior Herpes Simplex Keratitis

Use cautiously; consider antiviral coverage in patients with recent or recurrent HSV keratitis.

Active Uveitis

Avoid in active inflammation; can worsen.

Pseudophakic Eyes with Disrupted Posterior Capsule

Higher risk of cystoid macular edema; weigh benefit against risk.

Pregnancy and Breastfeeding

Prostaglandin analogs in animal studies have produced uterine contractions and adverse pregnancy effects at systemic exposures higher than ophthalmic dosing. Latanoprost is generally avoided during pregnancy when clinically feasible; alternative agents (such as a beta-blocker with punctal occlusion) are usually preferred. It is not known whether latanoprost is excreted in human breast milk in clinically meaningful amounts. Discuss with your obstetrician and ophthalmologist.

Latanoprost in the Treatment Ladder

For most patients with newly diagnosed open-angle glaucoma, latanoprost is the first-line drug because:

  • Strong IOP reduction (25-32%)
  • Once-daily dosing improves adherence
  • Minimal systemic side effects
  • Available generically at low cost
  • Long safety record since 1996

Patients who do not respond adequately, who do not tolerate the cosmetic effects, or who reach a plateau may add:

Frequently Asked Questions

Will my eyes really change color?

Iris darkening occurs gradually over 6-12 months in some patients, particularly those with mixed-color irises (hazel, green-brown). It is usually permanent - even after stopping the drop, the new pigment does not reverse. Patients with pure blue or pure brown eyes are less likely to notice a change, although it can still occur.

Why are my eyelashes growing?

Prostaglandins stimulate hair follicle activity. Eyelash growth (longer, thicker, darker lashes) is common with chronic prostaglandin use and can be cosmetically pleasing or noticeable, depending on the patient. The cosmetic eyelash drug Latisse uses bimatoprost - the same mechanism - applied to the lash line.

Why does latanoprost need to be refrigerated?

The original Xalatan formulation requires refrigeration before opening. After opening, it can be stored at room temperature for a limited period (commonly up to 6 weeks). Generic latanoprost products can have product-specific storage instructions, so check the label on your bottle.

What if I miss a dose?

Skip the missed dose if it is nearly time for the next; otherwise, take it as soon as you remember that day. Do not double up. Missing one dose does not produce a major pressure rise, but consistently skipped doses leave the eye unprotected.

How does latanoprost compare to other glaucoma drops?

Latanoprost (and other prostaglandins) provides the strongest single-drop pressure reduction, the most convenient dosing (once daily), and the best systemic safety profile. The trade-off is the cosmetic class effects (iris pigmentation, lash growth, periorbitopathy). For most patients, the trade-off favors the prostaglandin.

Is latanoprost safe to use long-term?

For most patients, yes. Latanoprost has been in clinical use since 1996 with extensive safety data. The relevant long-term concerns are the cosmetic class effects and rare reports of cystoid macular edema in selected eyes. Systemic side effects are much less common than with beta-blocker drops.

References

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