Drugs for Eye and Ear Disorders

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					Drugs for Eye and Ear Disorders

           Chapter 49
      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
                    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
                  Glaucoma
• Risk Factors:
  – Hypertension
  – Migraine headaches
  – Refractive disorders with high degree of myopia or
    hyperopia
  – Normal aging
• Diagnostics:
  – Tonometry
                  Glaucoma
• Types:
  – Closed-angle glaucoma
  – Open-angle glaucoma

  Compare and contrast the pathophysiology and
    characteristics of these two types of glaucoma.
             Glaucoma: Treatment
• Closed-angle                   • Open-angle
  – Laser or conventional          – Medications
    surgery                           • Prostaglandins
     •   Iridectomy                   • Beta-adrenergic blockers
     •   laser trabeculoplasty        • Alpha2-adrenergic
     •   trabeculectomy                 agonists
     •   drainage implants            • Carbonic anhydrase
                                        inhibitors
                                      • Cholinergic agonists
                                      • Nonselective
                                        sympathomimetics
                                      • Osmotic diuretics
          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
    Glaucoma Pharmacotherapy


Describe the two mechanisms by which
 pharmacotherapeutic agents decrease IOP
                   Prostaglandins
•   Newer therapy
•   Drug of choice
•   MOA: increase outflow of aqueous humor
•   Examples:
    –   latanoprost (Xalatan)
    –   Bimatoprost (Lumigan)
    –   travaprost (Travatan)
    –   unoprostone (Rescula)
• Administer before bedtime
         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)
       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?
     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
   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
               Question


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

What is an important nursing consideration
based on the fact that cholinergic agonists
have a greater risk of toxicity?
 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)
                 Questions
• What is the implication of “nonselective”?

• Dipivefrin is converted to epinephrine in the
  eye. What is the implication of this drug
  property?
              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
   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
      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
    Glaucoma Pharmacotherapy
          Client Teaching
• Immediately report:
  – Eye irritation       – pain
  – Conjunctival edema   – itching,
  – Burning              – sensation of foreign
                           body in the eye
  – Stinging
                         – Photophobia
  – Redness
                         – visual disturbances.
  – blurred vision
  Pharmacotherapy for Eye Exams
• Mydriatic drugs
• Cycloplegic drugs
• Examples:
  – Anticholinergics
     • atropine (Isopto Atropine)
     • tropicamide (Mydriacyl)
  – Sympathomimetic
     • phenylephrine (Mydfrin)
               Related Concerns
• Mydriatics                     • Cycloplegics
  – Intense photophobia             – Severe blurred vision
    and pain with bright light      – Loss of near vision
  – Can worsen glaucoma
  – Strong concentrations of        – Scopolomine, an
    cholinergics may have             anticholinergic has a
    CNS effedts                       cycloplegic effect
     • Confusion                      causing blurred vision
     • Unsteadiness                   and closed angle
     • Drowsiness                     glaucoma attacks
         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
               Ear Conditions
• Otitis
  – External
  – Media
  – Internal
• Mastoiditis
• Cerumen accumulation
       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
        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
        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
             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

				
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