Pilocarpine reduces intraocular pressure in open-angle glaucoma primarily by:

• A Shrinking the choroid and reducing uveoscleral inflow
• B Inhibiting aqueous secretion from the ciliary body epithelium
• C Relaxing the trabecular meshwork cells to increase outflow resistance gradient
• D Contracting the longitudinal ciliary muscle and pulling open the trabecular meshwork to increase conventional outflow ✓

Explanation

Pilocarpine is a direct muscarinic agonist. Contraction of the longitudinal fibres of the ciliary muscle pulls the scleral spur posteriorly, opening the intertrabecular spaces and increasing conventional trabecular outflow. It does not reduce aqueous secretion (that is the beta-blocker and carbonic anhydrase inhibitor mechanism), nor does it act on uveoscleral flow (the prostaglandin analogue target). Induced myopia and brow ache from ciliary spasm follow directly from this muscarinic action.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.