Latanoprost Eye Drop Dosing and Administration
Administer latanoprost 0.005% as one drop (1.5 μg) in the affected eye(s) once daily in the evening. 1
Dosing Guidelines
- Standard dose: One drop of latanoprost 0.005% once daily in the evening 1
- Timing is critical: Evening administration is specifically recommended, as IOP reduction begins 3-4 hours after instillation and peaks at 8-12 hours 1
- Do not exceed once-daily dosing: More frequent administration may paradoxically decrease IOP-lowering effect or cause IOP elevations 1
- If a dose is missed: Continue with the next scheduled dose; do not double up 1
Efficacy Profile
- IOP reduction magnitude: Latanoprost reduces IOP by 22-39% over treatment periods of 1-12 months, with sustained efficacy up to 2 years 2
- Absolute IOP reduction: Expect approximately 6-7.5 mmHg reduction from baseline 3, 4
- First-line status: The American Academy of Ophthalmology recommends prostaglandin analogs including latanoprost as first-line therapy due to superior efficacy (8.5 mmHg reduction) compared to alternatives like dorzolamide (5.6 mmHg) 5, 6
- Comparative effectiveness: Latanoprost is among the most efficacious drugs alongside bimatoprost and travoprost, though within-class differences are small and may not be clinically meaningful 7
Combination Therapy
- Spacing with other drops: When using multiple topical medications, administer at least 5 minutes apart to prevent washout 1, 5
- Additive effects: Latanoprost demonstrates significant additive IOP-lowering when combined with other glaucoma medications 2
- Fixed combination with timolol: Provides superior IOP reduction compared to either component alone for patients requiring multiple medications 7, 6
- Do not combine with other prostaglandins: The use of two or more prostaglandins or prostaglandin analogs together is not recommended 1
Common Pitfalls and Adverse Effects
- Iris pigmentation: Occurs in 2-10% of patients after 3-4.5 months of treatment and may be permanent 2, 8, 9
- Conjunctival hyperemia: Mild to moderate redness occurs in 3-15% of patients but rarely requires discontinuation 2, 9
- No systemic effects: Unlike beta-blockers, latanoprost does not produce cardiopulmonary adverse effects 2, 8
- Washout period: If discontinuing latanoprost, significant IOP-lowering effect is not observed beyond 4 weeks 7
Special Populations
- Pregnancy: Latanoprost has Pregnancy Category C rating; most ophthalmologists avoid prostaglandins during pregnancy due to theoretical risk of premature labor, though a small case series of 11 patients showed no adverse effects 7, 6
- Breastfeeding: May be considered during lactation, though caution is advised 7, 6
Mechanism and Clinical Context
- Mechanism of action: Increases uveoscleral outflow rather than affecting conventional trabecular-canalicular outflow 2, 8
- Duration of action: Single dose provides IOP-lowering for 20-24 hours, enabling once-daily dosing 8, 4
- Tolerability advantage: Favorable profile compared to other prostaglandin analogs per the American Academy of Ophthalmology 6