Pharmacology of glaucoma slideshare.pptx.

Glaucoma

1. Glaucoma

2. Parasympathetic nerves arise from the brain stem & sacral portion of the spinal cord. Pre ganglionic parasympathetic fibers from the cranial region are carried in the III ( occulomotor ), VII (facial), IX ( glossophyrangeal ) & X ( vagus ) nerves. The para sympathetic fibers from the sacral portion of the spinal cord are carried along the pelvic nerves , which arise from S 1 & S 2 .

3. Receptors in Eye Iris M 3 – Constrictor Pupillae α 1 - Dilator Pupillae Ciliary body M 3 – Ciliary muscle – Accommodation β – Ciliary epithelium – Aqueous Humor production

4. Eye Contraction of sphincter pupalae muscles (circular fibers of iris) causes: Miosis Widening of filtration angle (Opening of canal of schlemm) Contraction of ciliary muscles causes: Accommodation to near vision Opening of canal of schlemm intraocular pressure decreases due to better drainage through canal of Schlemm which occurs due to opening up of trabecular meshwork.

5. Glaucoma Increase intraocular pressure (↑ IOP) Normal 10 – 20 mmHg Visual field defects / ↓Visual Acuity Scotoma Tunnel vision Optic nerve damage Optic disc cupping Loss of vision is irreversible

6. Causes of Glaucoma Increase production of aqueous humor Decrease drainage of aqueous humor

7. Types of Glaucoma Open angle (Chronic) Gradual loss of vision Painless Closed angle (Acute congestive glaucoma) Sudden loss of vision Severe pain in eye, headache, nausea, vomiting Red eye usually

8. Treatment of Glaucoma Drugs Surgery Trabeculectomy (can be with Argon Laser) Canaloplasty

9. Drugs That Increase Aqueous Outflow Nonspecific Adrenergic Agonists (epinephrine , dipivefrin ) -Mechanism:  uveoscleral outflow of aqueous humor -Administration: Topical drops -Side Effects: Can precipitate acute attack in patients with narrow iris-corneal angle, headaches, cardiovascular arrhythmia, tachycardia

10. Parasympathomimetics ( pilocarpine , carbachol , echothiophate ) -Mechanism:  contractile force of ciliary body muscle,  outflow via TM -Administration: Topical drops or gel, (slow-release plastic insert) -Side Effects: Headache, induced miopia . Few systemic SE for direct-acting agonists vs. AchE inhibitors (diarrhea, cramps, prolonged paralysis in setting of succinylcholine).

11. Drugs That Decrease Aqueous Production Beta-Blockers ( levobunolol , timolol , carteolol , betaxolol ) -Mechanism: Act on ciliary body to  production of aqueous humor -Administration: Topical drops to avoid systemic effects -Side Effects: Cardiovascular ( bradycardia , asystole , syncope), bronchoconstriction (avoid with b1-selective betaxolol ), depression

12. Alpha-2 Adrenergic Agonists ( apraclonidine , brimonidine ) -Mechanism:  production of aqueous humor -Administration: Topical drops -Side Effects: Lethargy, fatigue, dry mouth [ apraclonidine is a derivative of clonidine (antihypertensive) which cannot cross BBB to cause systemic hypotension]