Latanoprost
Prostaglandin analogue eye drops for glaucoma and ocular hypertension
Quick Facts About Latanoprost
Key Takeaways About Latanoprost
- Once-daily evening dosing: Apply one drop in the affected eye(s) each evening – more frequent use may actually reduce effectiveness
- Iris color may change permanently: Latanoprost can gradually increase brown pigmentation in the iris, especially in mixed-color eyes
- Contact lens caution: Remove contact lenses before applying and wait at least 15 minutes before reinserting
- Store correctly: Keep unopened bottles refrigerated (2–8 °C); once opened, use within 4 weeks at room temperature (up to 25 °C)
- Safe for children: Approved for pediatric use from birth, though not studied in premature infants born before week 36
What Is Latanoprost and What Is It Used For?
Latanoprost is a prostaglandin F2-alpha analogue eye drop that lowers intraocular pressure (IOP) by increasing the natural outflow of aqueous humor from the eye. It is primarily used to treat open-angle glaucoma and ocular hypertension in adults and children of all ages.
Latanoprost belongs to a group of medications known as prostaglandin analogues. These drugs work by mimicking the action of naturally occurring prostaglandins in the body to increase the uveoscleral outflow of aqueous humor – the clear fluid that fills the front part of the eye. By enhancing this drainage, latanoprost effectively reduces the pressure inside the eye, which is the primary modifiable risk factor in glaucoma.
The medication is approved for two main conditions. Open-angle glaucoma is the most common form of glaucoma, a progressive optic neuropathy characterized by damage to the optic nerve, often associated with elevated intraocular pressure. Left untreated, it can lead to irreversible vision loss and blindness. Ocular hypertension refers to elevated eye pressure without any detectable optic nerve damage – a condition that significantly increases the risk of developing glaucoma over time.
Latanoprost is one of the most widely prescribed medications in ophthalmology worldwide. According to the American Academy of Ophthalmology (AAO) and the European Glaucoma Society (EGS), prostaglandin analogues including latanoprost are recommended as first-line therapy for most patients with open-angle glaucoma due to their excellent efficacy, once-daily dosing convenience, and favorable safety profile. Clinical studies have demonstrated that latanoprost typically reduces IOP by 25–35% from baseline.
The medication is approved for use in adults (including elderly patients) as well as children from birth to 18 years of age. However, it has not been tested in premature infants born before gestational week 36. The pediatric approval makes latanoprost a valuable treatment option for childhood glaucoma, which, although rare, can cause significant visual impairment if not managed promptly.
Glaucoma is often called the "silent thief of sight" because it typically causes no symptoms until significant vision loss has occurred. The World Health Organization (WHO) estimates that glaucoma is the second leading cause of blindness globally, affecting over 80 million people. Regular eye examinations including IOP measurement are crucial for early detection, particularly for those over 40, people with a family history of glaucoma, and individuals with other risk factors such as high myopia or diabetes.
How Does Latanoprost Work?
Latanoprost is a prodrug – an inactive form that is converted to its active metabolite, latanoprost acid, after absorption through the cornea. Once activated, it binds to prostaglandin FP receptors in the ciliary muscle of the eye, triggering a cascade of cellular changes that remodel the extracellular matrix in the uveoscleral outflow pathway. This remodeling increases the spaces between muscle fibers, allowing aqueous humor to drain more easily from the anterior chamber of the eye.
The onset of IOP reduction typically occurs within 3–4 hours of administration, with peak effect reached at approximately 8–12 hours. The pressure-lowering effect is maintained for at least 24 hours, which allows for convenient once-daily dosing. Studies have shown that evening administration produces optimal IOP reduction throughout the following day, which is why dosing in the evening is recommended.
What Should You Know Before Using Latanoprost?
Do not use latanoprost if you are allergic to it or any of its ingredients. Inform your doctor about any eye conditions, planned eye surgery, severe asthma, contact lens use, or pregnancy before starting treatment. Latanoprost is not recommended during pregnancy or breastfeeding.
Contraindications
Do not use latanoprost if you have a known allergy (hypersensitivity) to latanoprost or any of the other ingredients in the formulation, including the preservative benzalkonium chloride. Signs of an allergic reaction may include severe eye irritation, swelling around the eyes, skin rash, or difficulty breathing.
Warnings and Precautions
Before you or your child starts using latanoprost, speak to your doctor or pharmacist if any of the following apply:
- Eye surgery: If you are about to undergo or have recently had eye surgery, including cataract surgery. Latanoprost may increase the risk of complications such as macular edema following surgery.
- Eye problems: If you suffer from eye pain, irritation, inflammation (uveitis or iritis), or blurred vision. These conditions may be worsened by latanoprost or may require adjusted treatment.
- Dry eyes: If you have known dry eye syndrome. The preservative benzalkonium chloride in latanoprost can exacerbate dry eye symptoms, particularly with long-term use.
- Severe or uncontrolled asthma: Although rare, latanoprost has been associated with worsening of asthma in some patients. If you have severe or poorly controlled asthma, discuss risks with your doctor.
- Contact lenses: You can still use latanoprost while wearing contact lenses, but you must follow specific instructions (see the dosage section for detailed guidance).
- Herpes simplex virus: If you have had or currently have a viral eye infection caused by herpes simplex virus (HSV), inform your doctor. Latanoprost may potentially reactivate HSV keratitis.
Latanoprost may gradually increase the amount of brown pigment in the colored part of the eye (iris). If you have mixed-color eyes (blue-brown, grey-brown, yellow-brown, or green-brown), this color change is more likely to occur than in people with uniformly colored eyes. The change may develop over months to years, may become permanent, and may be more noticeable if you use latanoprost in only one eye. If you are treating both eyes, both eyes may change color. No associated eye health problems have been identified.
Pregnancy and Breastfeeding
Pregnancy: Latanoprost should not be used during pregnancy unless clearly necessary. Animal studies have shown some adverse effects, and there are insufficient data in pregnant women. The unborn child could be affected. If you are pregnant, think you may be pregnant, or are planning to become pregnant, seek advice from your doctor before using this medication.
Breastfeeding: It is not known whether latanoprost passes into human breast milk. Because many drugs are excreted in breast milk, latanoprost should not be used during breastfeeding. Consult your doctor before using this medication while breastfeeding.
Fertility: There is limited data on the effect of latanoprost on human fertility. Animal studies have not shown impaired fertility at clinically relevant doses.
Driving and Operating Machinery
When you apply latanoprost, you may experience temporary blurred vision. If this occurs, do not drive or operate machinery until your vision clears. This effect is usually brief and resolves within a few minutes of application.
Benzalkonium Chloride
Latanoprost eye drops contain the preservative benzalkonium chloride (0.2 mg per mL). This preservative can be absorbed by soft contact lenses and may discolor them. Remove contact lenses before applying the drops and wait at least 15 minutes before reinserting them. Benzalkonium chloride may also be irritating to the eyes, especially in patients with dry eyes or corneal disorders. If you experience irritation, stinging, or pain after using the medication, contact your doctor.
How Does Latanoprost Interact with Other Drugs?
Latanoprost may interact with other eye drops, particularly other prostaglandin analogues (which can paradoxically increase eye pressure). If using multiple eye medications, wait at least 5 minutes between each drop. Always inform your doctor about all medications you are using.
Drug interactions with latanoprost are relatively limited compared to systemic medications, primarily because it is administered topically to the eye with minimal systemic absorption. However, some interactions are clinically important and should be discussed with your healthcare provider.
| Interacting Drug | Type | Effect | Recommendation |
|---|---|---|---|
| Other prostaglandin analogues (bimatoprost, travoprost, tafluprost) | Major | Paradoxical increase in intraocular pressure | Avoid concomitant use |
| Timolol (beta-blocker eye drops) | Additive | Enhanced IOP-lowering effect; combination available as Xalcom | Monitor – often used together intentionally |
| Ophthalmic NSAIDs (diclofenac, ketorolac eye drops) | Moderate | May reduce IOP-lowering efficacy | Separate administration by at least 5 minutes |
| Thimerosal-containing eye drops | Moderate | Precipitation may occur when combined | Wait at least 5 minutes between applications |
If you are using multiple eye medications, always wait at least 5 minutes between each different eye drop to prevent dilution and to ensure adequate absorption. Applying drops too close together can wash away the first medication before it has been fully absorbed.
Tell your doctor or pharmacist about all medicines you or your child are currently using, have recently used, or might use in the future. This includes prescription medicines, over-the-counter products, herbal remedies, and nutritional supplements.
What Is the Correct Dosage of Latanoprost?
The standard dose for all age groups is one drop in the affected eye(s) once daily in the evening. Do not use more than once per day, as more frequent dosing may reduce effectiveness. Remove contact lenses before applying and wait 15 minutes before reinserting.
Always use latanoprost exactly as your doctor has instructed. If you are unsure, consult your doctor or pharmacist. The recommended dosage is the same for all age groups, including adults, elderly patients, and children.
Adults (Including Elderly)
Standard Adult Dosing
Dose: One drop in the affected eye(s) once daily
Timing: Evening (best time for optimal pressure reduction)
Duration: Continue as directed by your doctor – treatment is typically long-term
Maximum frequency: Once daily – do not exceed this as it may reduce effectiveness
Children (From Birth to 18 Years)
Pediatric Dosing
Dose: One drop in the affected eye(s) once daily
Timing: Evening
Note: The same dose and frequency as adults. Not tested in premature infants born before week 36.
How to Apply Latanoprost Eye Drops
Follow these steps to apply your eye drops correctly:
- Wash your hands thoroughly and sit or stand in a comfortable position.
- Twist off the cap from the bottle.
- Gently pull down the lower eyelid of the affected eye using your finger to create a small pocket.
- Position the bottle tip close to, but not touching, the eye.
- Squeeze the bottle gently so that exactly one drop enters the eye. Release the lower eyelid.
- Apply punctal occlusion: Press a finger against the inner corner of the eye (nearest to the nose) and hold for 1 minute while keeping the eye closed. This minimizes systemic absorption and helps the medication stay in the eye.
- Repeat for the other eye if your doctor has instructed you to treat both eyes.
- Replace the cap securely on the bottle.
If you wear contact lenses, remove them before applying latanoprost. Wait at least 15 minutes after instilling the drops before reinserting your lenses. The preservative benzalkonium chloride can be absorbed by soft contact lenses, potentially causing irritation and discoloration.
Missed Dose
If you forget to apply your latanoprost drops, simply continue with your regular dosing schedule at the usual time the next evening. Do not apply a double dose to make up for the missed one. If you are unsure about what to do, contact your doctor or pharmacist.
Overdose
If you accidentally apply too many drops to the eye, you may experience mild eye irritation, conjunctival redness (hyperemia), and tearing. These effects should be temporary. If symptoms persist or if you are concerned, contact your doctor.
If latanoprost is accidentally swallowed, contact your doctor, hospital, or poison control center immediately for assessment and advice. Symptoms of systemic overdose may include nausea, abdominal pain, dizziness, and fatigue.
Latanoprost is typically a long-term treatment. Do not stop using it without talking to your doctor, as untreated elevated intraocular pressure can lead to progressive optic nerve damage and irreversible vision loss. If you wish to discontinue treatment or are experiencing side effects, your doctor can advise on alternatives.
What Are the Side Effects of Latanoprost?
The most common side effects include gradual iris color change (increased brown pigment), eye redness, eye irritation, and changes to eyelashes (longer, darker, thicker). Most side effects are mild and occur locally in the eye. Serious side effects such as macular edema or worsening of asthma are uncommon.
Like all medicines, latanoprost can cause side effects, although not everybody experiences them. The following side effects have been reported by patients using latanoprost eye drops.
Very Common
- Iris color change: Gradual increase in brown pigmentation of the iris. More likely in mixed-color eyes (blue-brown, grey-brown, yellow-brown, green-brown). Usually develops within 8 months. May be permanent. No associated health problems.
- Conjunctival hyperemia: Redness of the white part of the eye
- Eye irritation: Burning, grittiness, itching, stinging, or a feeling of something in the eye
- Eyelash changes: Gradual darkening, lengthening, thickening, and increased number of eyelashes (most commonly reported in patients of Japanese descent)
Common
- Superficial corneal damage (punctate keratitis)
- Eyelid inflammation (blepharitis)
- Eye pain
- Light sensitivity (photophobia)
- Conjunctivitis (pink eye)
Uncommon
- Swollen eyelids, dry eyes
- Keratitis (corneal inflammation), blurred vision
- Uveitis (inflammation of the iris and surrounding tissue)
- Macular edema (swelling of the retina)
- Skin rash
- Chest pain (angina pectoris), palpitations
- Asthma symptoms, shortness of breath (dyspnea)
- Headache, dizziness
- Muscle and joint pain
- Nausea, vomiting
Rare
- Iritis (inflammation of the iris)
- Corneal erosion or edema
- Periorbital edema (swelling around the eye)
- Misdirected eyelashes (trichiasis) or extra row of eyelashes (distichiasis)
- Iris cyst (fluid-filled blister on the iris)
- Darkened eyelid skin
- Worsening of asthma
- Severe skin itching
- Reactivation of herpes simplex virus (HSV) keratitis
Very Rare
- Worsening of angina pectoris in patients with pre-existing heart disease
- Periorbital and eyelid fat atrophy (sunken appearance around the eyes – deepening of the eyelid sulcus)
- Corneal calcification (calcium deposits on the cornea, very rare, mainly in patients with pre-existing severe corneal damage)
Side Effects in Children
Side effects that are more frequently reported in children compared to adults include runny and itchy nose (rhinitis) and fever. The ocular side effects in children are generally similar to those observed in adults.
If you experience severe eye irritation that causes excessive tearing or makes you consider stopping the medication, contact your doctor promptly (within a week). Your treatment may need to be reassessed to ensure you are receiving the most appropriate therapy for your condition. If you experience sudden vision changes, severe eye pain, or signs of an allergic reaction (swelling, rash, difficulty breathing), seek medical attention immediately.
How Should You Store Latanoprost?
Store unopened bottles in the refrigerator (2–8 °C) in the original carton. Once opened, store at room temperature (up to 25 °C) and discard after 4 weeks, even if solution remains. Keep out of reach of children.
Proper storage of latanoprost is essential to maintain its effectiveness and safety. The medication is sensitive to temperature and light, so following storage instructions carefully is important.
| Condition | Storage Requirement |
|---|---|
| Unopened bottle | Refrigerate at 2–8 °C (36–46 °F), in the original carton to protect from light |
| Opened bottle | Store at room temperature up to 25 °C (77 °F) |
| Opened shelf life | Discard 4 weeks after opening, even if solution remains |
| Expiry date | Do not use after the expiry date on the carton and bottle (last day of stated month) |
Keep this medication out of sight and reach of children. Do not dispose of medicines via household waste or sewage. Ask your pharmacist how to dispose of medicines that are no longer needed. These measures help to protect the environment.
What Does Latanoprost Contain?
Each milliliter of latanoprost eye drops contains 50 micrograms of the active substance latanoprost. Each bottle contains 2.5 mL of solution (approximately 80 drops). One drop contains approximately 1.5 micrograms of latanoprost.
Active Ingredient
The active substance is latanoprost. Each 1 mL of eye drop solution contains 50 micrograms of latanoprost. A standard 2.5 mL bottle contains 125 micrograms of latanoprost in total, providing approximately 80 drops. Each individual drop delivers approximately 1.5 micrograms of latanoprost to the eye.
Inactive Ingredients (Excipients)
The other ingredients in the formulation serve various purposes, including preservation, pH buffering, and tonicity adjustment:
- Benzalkonium chloride – preservative (0.2 mg/mL)
- Sodium dihydrogen phosphate monohydrate – pH buffer
- Disodium phosphate – pH buffer
- Sodium chloride – tonicity agent
- Purified water – vehicle/solvent
Appearance and Packaging
Latanoprost eye drops are a clear, colorless solution in a plastic dropper bottle with a child-resistant screw cap. Each bottle contains 2.5 mL of solution. The medication is available in pack sizes of 1×2.5 mL, 3×2.5 mL, and 6×2.5 mL. Not all pack sizes may be available in all markets.
Frequently Asked Questions About Latanoprost
Medical References
All medical information on this page is based on peer-reviewed research and international clinical guidelines. Evidence level: 1A.
- European Medicines Agency (EMA). Latanoprost – Summary of Product Characteristics (SmPC). EMA Product Database. Available at: ema.europa.eu
- U.S. Food and Drug Administration (FDA). Xalatan (latanoprost ophthalmic solution) – Prescribing Information. FDA Label. 2024.
- European Glaucoma Society. Terminology and Guidelines for Glaucoma. 5th Edition, 2020. PubliComm, Savona, Italy.
- American Academy of Ophthalmology. Preferred Practice Pattern: Primary Open-Angle Glaucoma. Ophthalmology. 2020;127(1):P183–P227.
- Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of glaucoma: a review. JAMA. 2014;311(18):1901–1911. doi:10.1001/jama.2014.3192
- Alm A, Stjernschantz J. Effects on intraocular pressure and side effects of 0.005% latanoprost applied once daily, evening or morning: a comparison with timolol. Ophthalmology. 1995;102(12):1743–1752.
- World Health Organization (WHO). World Report on Vision. 2019. Geneva: WHO.
- National Institute for Health and Care Excellence (NICE). Glaucoma: diagnosis and management. NICE guideline [NG81]. 2017 (updated 2022).
- British National Formulary (BNF). Latanoprost monograph. BNF. 2024. Available at: bnf.nice.org.uk
- Parrish RK, Palmberg P, Sheu WP; XLT Study Group. A comparison of latanoprost, bimatoprost, and travoprost in patients with elevated intraocular pressure: a 12-week, randomized, masked-evaluator multicenter study. Am J Ophthalmol. 2003;135(5):688–703.
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