LATANOPOST EYE DROPS

Indications

• Open-angle glaucoma
• Ocular hypertension

Dosage

Children: Refer to the BNF for Children for appropriate dosing in paediatric patients.

Adults: The usual dosage is one drop in the affected eye(s) once daily in the evening.

Mechanism of action

Latanoprost is a selective FP receptor agonist, which mimics the action of prostaglandin F2α. It binds to the FP receptors in the ciliary body, leading to increased uveoscleral outflow of aqueous humor. This mechanism helps to reduce intraocular pressure effectively.

Pharmacodynamics

The pharmacodynamic effects of latanoprost include a reduction in intraocular pressure through enhanced aqueous humor drainage. The onset of action is typically observed within 2 hours of administration, with peak effects occurring at approximately 8 to 12 hours. The duration of the effect can last for over 24 hours, allowing for once-daily dosing.

Pharmacokinetics

Latanoprost is well absorbed through the cornea after topical administration. It is rapidly metabolized to its active form, latanoprost acid, which is responsible for its therapeutic effects. The systemic bioavailability is low due to extensive first-pass metabolism. The elimination half-life of latanoprost acid is approximately 17 minutes in plasma, with renal excretion being the primary route of elimination.

Contra-indications

• Hypersensitivity to latanoprost or any of its components
• Active intraocular inflammation

Adverse effects

• Conjunctival hyperemia
• Iris pigmentation changes
• Eyelash changes (increased length, thickness, and pigmentation)
• Ocular pruritus
• Dry eyes
• Blurred vision

Interactions

• May interact with other ocular hypotensive agents, potentially leading to additive effects
• Caution should be exercised when used with prostaglandin analogs

Precautions

• Use with caution in patients with a history of herpetic keratitis
• May cause darkening of the iris, which is irreversible
• May cause eyelash changes that are also irreversible

Pregnancy

Latanoprost should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal studies have shown reproductive toxicity.

Breast-feeding

It is not known whether latanoprost is excreted in human milk. A decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Storage

Store at 2-8°C. Do not freeze. Once opened, the product should be used within 4 weeks.

Formulations

• 0.005% eye drops
• Preservative-free formulations are also available