Drugs for Eye and Ear Disorders

1. Drugs for Eye and Ear Disorders Chapter 49

2. Intraocular Pressure (IOP) Normal range maintained by an equilibrium of aqueous humor production and outflow. Median adult IOP: 15 – 16 mm Hg Varies with age, daily activities, time of day General rule of thumb: > 21 mm Hg abnormal > 30 mm Hg requires treatment

3. Glaucoma Leading preventable cause of blindness. Occurs when IOP high enough to cause damage to the optic nerve: Loss of visual fields ? possibly advancing to blindness Causes: Primary condition Secondary to eye trauma, infection, DM, inflammation, hemorrhage, tumor or cataracts; some medications may contribute to development

4. Glaucoma Risk Factors: Hypertension Migraine headaches Refractive disorders with high degree of myopia or hyperopia Normal aging Diagnostics: Tonometry

5. Glaucoma Types: Closed-angle glaucoma Open-angle glaucoma Compare and contrast the pathophysiology and characteristics of these two types of glaucoma.

6. Glaucoma: Treatment Closed-angle Laser or conventional surgery Iridectomy laser trabeculoplasty trabeculectomy drainage implants Open-angle Medications Prostaglandins Beta-adrenergic blockers Alpha2-adrenergic agonists Carbonic anhydrase inhibitors Cholinergic agonists Nonselective sympathomimetics Osmotic diuretics

7. Principles of Glaucoma Pharmacotherapy Treatment must begin when experiencing visual field changes or evidence of optic nerve damage– regardless of IOP Some drugs take 6 to 8 weeks to work Therapy is evaluated after 2- 4 months of pharmacotherapy Second drug added if therapeutic effect not achieved Effects of some drugs continue for 2 – 4 weeks after stopping

8. Glaucoma Pharmacotherapy Describe the two mechanisms by which pharmacotherapeutic agents decrease IOP

9. Prostaglandins Newer therapy Drug of choice MOA: increase outflow of aqueous humor Examples: latanoprost (Xalatan) Bimatoprost (Lumigan) travaprost (Travatan) unoprostone (Rescula) Administer before bedtime

10. Beta-Adrenergic Blockers MOA: decreases production of aqueous humor by ciliary body Fewer ocular adverse effects than cholinergic agonists or sympathomimetics Examples: betaxolol (Betoptic) larteolol (Ocupress) Levobunolol (Betegan) metipranolol (OptiPranolol) timolol (Timoptic; Timoptix XE)

11. Beta-Adrenergic Blockers Topical administration does not result in significant systemic absorption If systemic absorption does occur what s/s would you expect to see? In which conditions should these medications be used cautiously?

12. Alpha2-Adrenergic Agonists MOA: decrease production of aqueous humor Examples: apraclonidine (Lopidine) brimonidine (Alphagan) Fewer cardiovascular or pulmonary side effects Most significant side effects: Headache, drowsiness, dry mucousal membranes, blurred vision, irritated eyelids

13. Carbonic Anhydrase Inhibitors Topical or systemic administration MOA: decrease production of aqueous humor Examples: Topical: dorzolamide (Trusopt) Generally well tolerated and few side effects Oral: acetazolamide (Diamox) Rarely used; more systemic side effects than other classes Contain sulfur (? risk of allergic reaction) Exert diuretic effects and quickly ? IOP

14. Question Identify an important nursing consideration during the administration of a carbonic anhydrase inhibitor.

15. Cholinergic Agonists (Miotics) MOA: Constrics pupil and contracts ciliary muscle ? stretching of trabecular meshwork, allowing greater outflow of aqueous humor Most commonly prescribed in class: Pilocarpine (Adsorbocarpine, Isopto Carpine) Greater toxicity than other antiglaucoma agents Adverse effects: Headache, induced myopia, decreased vision in low light

16. Question What is an important nursing consideration based on the fact that cholinergic agonists have a greater risk of toxicity?

17. Nonselective Sympathomimetics For treatment of open-angle glaucoma MOA: produce mydriasis and increase outflow of aqueous humor ? ? IOP Topical application with risk of systemic absorption Second-choice drugs Examples: dipivefrin (Propine) epinephryl borate (Epinal)

18. Questions What is the implication of “nonselective”? Dipivefrin is converted to epinephrine in the eye. What is the implication of this drug property?

19. Osmotic Diuretics Occasional use: Pre-op before ocular surgery Acute closed-angle glaucoma attack Examples: glycerin anhydrous (Opthalgan) isosorbide (Ismotic) mannitol (Osmitrol) Side effects: Headache, tremors, dizziness, dry mouth, fluid and electrolyte imbalances, thrombophlebitis or venour clot formation near IV administration site

20. Glaucoma Pharmacotherapy: General Nursing Considerations Thorough health history 2° or 3° heart block, bradycardia, heart failure, COPD Baseline data prior to initiation BP and pulse Beta-blocker- Teach pt. to take pulse and BP Establish acceptable parameters and when to call HCP Determine any factor that could affect compliance

21. Glaucoma Pharmacotherapy Client Teaching Review proper administration technique Remove fall risks in home Remove contact lenses (15 min) Remain still until blurred vision clears Report adverse reactions Report possibility of pregnancy

22. Glaucoma Pharmacotherapy Client Teaching Immediately report: Eye irritation Conjunctival edema Burning Stinging Redness blurred vision pain itching, sensation of foreign body in the eye Photophobia visual disturbances.

23. Pharmacotherapy for Eye Exams Mydriatic drugs Cycloplegic drugs Examples: Anticholinergics atropine (Isopto Atropine) tropicamide (Mydriacyl) Sympathomimetic phenylephrine (Mydfrin)

24. Related Concerns Mydriatics Intense photophobia and pain with bright light Can worsen glaucoma Strong concentrations of cholinergics may have CNS effedts Confusion Unsteadiness Drowsiness Cycloplegics Severe blurred vision Loss of near vision Scopolomine, an anticholinergic has a cycloplegic effect causing blurred vision and closed angle glaucoma attacks

25. Pharmacotherapy for Minor Eye Conditions Lubricants Vasoconstrictors phenylephrine (Neo-synephrine) naphazoline (Clear Eyes) tetrahydrozoline (Murine-Plus, Visine) Vasoconstrictor side effects: Blurred vision, tearing, headache, rebound vasodilation with redness

26. Ear Conditions Otitis External Media Internal Mastoiditis Cerumen accumulation

27. Pharmacotherapy for Ear Conditions Ear Infections Topical otic antibiotic chloramphenicol (Chloromycetin, Pentamycetin) ciprofloxacin (Cipro) Systemic antibiotics Mastoiditis Trial of systemic antibiotics, surgery if ineffective Cerumen accumulation Wax softeners

28. Nursing Considerations If ear drum is perforated and client is hypersensitive to hydrocortisone, neomycin sulfate, or polymixin B– Do Not Use Chloramphenical contraindicated in hypersensitivity and ear drum perforation Cleanse ear and remove cerumen prior to instillation Warm otic drops to body temperature only

29. Lifespan Considerations Elderly and children most likely to experience ear infections < 3 years: gently pull pinna down and back before instilling otic drops > 3 years: hold pinna up and back

30. Client Teaching Chloramphenical drops can cause dizziness– lie down to instil Run water over otic drops to warm to body temp Do not touch dropper to the ear Massage the area around the ear gently after instillation Lie on opposite side for 5 minutes after instillation