Latanoprost eye drops are prescribed for open-angle glaucoma. The mechanism of intraocular pressure reduction and the characteristic ocular adverse effect are:

• A Increased uveoscleral outflow; iris hyperpigmentation and eyelash growth ✓
• B Increased trabecular outflow; transient myopia
• C Reduced aqueous humour formation via the ciliary body; punctate keratitis
• D Osmotic dehydration of the vitreous; conjunctival hyperaemia

Explanation

Latanoprost is a PGF2-alpha analogue acting on FP receptors in the ciliary muscle, relaxing the musculature and widening the spaces between muscle bundles to enhance uveoscleral outflow. It lowers intraocular pressure more effectively than timolol and is given once daily. Characteristic adverse effects are gradual darkening of iris colour, especially in hazel or green-brown eyes, elongation and darkening of eyelashes, and conjunctival hyperaemia. Beta blockers reduce aqueous secretion, a different mechanism entirely.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

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Written and medically reviewed by the StethoPrep medical team.