LATANOPROST
Clinical safety rating: safe
Animal studies have demonstrated safety
Latanoprost is a prostaglandin F2α analogue that acts as a selective FP receptor agonist. It increases uveoscleral outflow of aqueous humor by binding to prostanoid FP receptors in the ciliary muscle, leading to matrix metalloproteinase activation and remodeling of the extracellular matrix, thereby reducing intraocular pressure.
| Metabolism | Metabolized primarily by hydrolysis in the cornea to the active acid form (latanoprost acid) via esterases. The active moiety is further metabolized in the liver via beta-oxidation and oxidation to inactive metabolites. Enzymes involved include cytochrome P450 (CYP) enzymes (CYP2C8, CYP2D6) to a minor extent. |
| Excretion | Renal: 88% (metabolites); fecal: 6% (metabolites); unchanged latanoprost is not excreted renally. |
| Half-life | Terminal half-life of latanoprost acid is 17 minutes (0.28 hours) systemically; clinically, intraocular pressure reduction persists for 24 hours due to prolonged receptor binding. |
| Protein binding | Latanoprost acid: 99.5% bound to serum albumin in plasma. |
| Volume of Distribution | 0.12 L/kg; small volume indicates limited distribution into tissues. |
| Bioavailability | Ophthalmic: 100% locally via cornea; systemic: very low due to hydrolysis in cornea and plasma (no oral data, as not used systemically). |
| Onset of Action | Ophthalmic: 3-4 hours; maximal effect at 8-12 hours. |
| Duration of Action | Ophthalmic: Intraocular pressure reduction lasts at least 24 hours with once-daily dosing. |
| Molecular Weight | 432.59 |
Instill one drop (1.5 mcg) of 0.005% ophthalmic solution into the affected eye(s) once daily in the evening.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | Safety and efficacy in pediatric patients have not been established; use is not recommended. |
| Geriatric use | No dose adjustment required; same dosing as adults. |
| 1st trimester | Avoid unless benefit outweighs risk; based on animal studies showing reproductive toxicity. |
| 2nd trimester | Use only if clearly needed; no adequate human studies. |
| 3rd trimester | Not recommended near term due to potential for premature labor or fetal effects. |
Clinical note
No significant drug interactions Can cause increased pigmentation of the iris and eyelashes.
| Placental transfer | Demonstrated in animal studies; extent in humans unknown. |
| Breastfeeding | Latanoprost and its metabolites may be excreted in human milk. Caution should be exercised when administered to a nursing woman. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Common Effects | ocular hypertension |
| Serious Effects |
Hypersensitivity to latanoprost or any component of the formulation
| Precautions | May cause increased pigmentation of the iris (iridal melanin), periorbital skin darkening, and increased growth, thickness, and number of eyelashes. Use with caution in patients with intraocular inflammation (e.g., iritis/uveitis), aphakic patients, pseudophakic patients with a torn posterior lens capsule, or those with risk factors for macular edema. Can cause transient blurred vision. Patients should be monitored for ocular adverse effects. |
| Food/Dietary | No significant food interactions. Avoid excessive caffeine as it may increase intraocular pressure. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | Latanoprost is classified as FDA Pregnancy Category C. In animal studies, intravenous administration at doses 80 times the human exposure caused embryofetal toxicity including skeletal abnormalities and increased resorptions. No adequate human studies exist. The risk to the human fetus is unknown; however, the low systemic absorption (less than 5% of applied dose) after topical ocular administration likely minimizes fetal exposure. Use only if potential benefit justifies risk. |
| Fetal Monitoring | No specific maternal or fetal monitoring is required beyond standard prenatal care. However, because of the potential for systemic effects (e.g., bradycardia, bronchospasm) with prostaglandin analogs, monitor for changes in maternal heart rate, blood pressure, and respiratory status, especially in patients with asthma or cardiac conditions. |
| Fertility Effects | Animal studies have shown no impairment of fertility at doses up to 250 mcg/kg/day (approximately 280 times the human exposure). No human data are available; however, based on low systemic absorption, significant effects on fertility are unlikely. |
| Clinical Pearls | Apply gentle pressure to the nasolacrimal duct after instillation to reduce systemic absorption. Avoid use in patients with intraocular inflammation or known macular edema. Grapefruit juice may increase systemic exposure. Store unopened bottles at 2-8°C; opened bottles at room temperature up to 6 weeks. |
| Patient Advice | Remove contact lenses before instillation and wait at least 15 minutes before reinserting. · Wash hands before and after administration. · Tilt head back, pull down lower eyelid, and instill one drop in the affected eye(s). · Do not touch the dropper tip to any surface to avoid contamination. · May cause gradual change in eye color (increased brown pigmentation), which is permanent. · May cause eyelash growth, darkening, and thickening. · Report any eye pain, redness, or vision changes promptly. |