CHAPTER 57 Ophthalmic Drugs

Structures of the Eye Eyebrows, eyelids, eyelashes Palpebral fissure Sclera Uvea Choroid Iris Ciliary body

Structures of the Eye (cont’d) Conjunctiva Pupil Medial canthus Lacrimal caruncle Lacrimal glands Lateral canthus

Layers of the Eye All protected by the eyelid Protective external layer Cornea and sclera Middle layer Choroid, iris, ciliary body Internal layer Light-sensitive retina

Eye Muscles Each eye is held in place and moved by six muscles Rectus (four total) Oblique (two total)

Interior of the Eyeball Anterior chamber Posterior chamber Canal of Schlemm Aqueous humor Vitreous humor

Interior of the Eyeball (cont’d) Retina Rods Cones Optic nerve

Lens Accommodation Cataracts

Drugs That Affect the Eye Mydriatics Dilate the pupil Miotics Constrict the pupil Cycloplegics Paralyze the ciliary body Have mydriatic properties Cycloplegia: paralysis of accommodation

Ocular Drugs Antiglaucoma drugs Antimicrobial and antiinflammatory drugs Topical anesthetics Diagnostic drugs Antiallergic drugs Lubricants and moisturizers

Glaucoma Inhibition of the normal flow and drainage of aqueous humor Results in increased intraocular pressure (IOP) Pressure against the retina destroys neurons, leading to impaired vision and eventual blindness

Types of Glaucoma Angle-closure glaucoma Open-angle glaucoma Also characterized by underlying cause Primary Secondary Congenital

Drugs Used to Reduce IOP Beta-blockers (antiadrenergic) Osmotic diuretics Carbonic anhydrase inhibitors Direct-acting and indirect-acting parasympathomimetics (cholinergic) Prostaglandin agonists Sympathomimetics (adrenergics, mydriatics)

Cholinergic Drugs Mimic the PSNS neurotransmitter ACh Also called miotics, cholinergics Direct-acting and indirect-acting drugs Cause pupillary constriction (miosis), which leads to reduced IOP caused by increased outflow of aqueous humor

Cholinergic Drugs (cont’d) Direct-acting drugs acetylcholine (Miochol-E) carbachol (Carboptic) pilocarpine (Pilocar) (also ocular insert form) Indirect-acting drugs echothiophate (Phospholine Iodide)

Cholinergic Drugs: Indications Open-angle glaucoma Angle-closure glaucoma Ocular surgery Convergent strabismus (“cross-eye”) Ophthalmologic exams

Cholinergic Drugs: Adverse Effects Most limited to local effects If sufficient amounts enter the bloodstream, systemic effect may occur (most likely with indirect-acting) Hypotension, bradycardia, or tachycardia Headache, nausea, vomiting, diarrhea, abdominal cramps, asthma attacks Others

Sympathomimetics Mimic the sympathetic neurotransmitters epinephrine and norepinephrine Stimulate the dilator muscle to contract Result is increased pupil size (mydriasis) Enhance aqueous humor outflow through the canal of Schlemm IOP is reduced

Sympathomimetics (cont’d) brimonidine (Alphagan) apraclonidine (Iopidine) epinephryl (Epinal) dipivefrin (Propine) Prodrug of epinephrine When applied topically Hydrolyzed to epinephrine Penetrates tissues better

Sympathomimetics: Indications Chronic, open-angle glaucoma (to reduce IOP) Reduction of perioperative IOP Reduction of ocular hypertension

Sympathomimetics: Adverse Effects Primarily limited to ocular effects Burning Eye pain Lacrimation Rare systemic effects Hypertension Tachycardia Headache Faintness

Beta-Adrenergic Blockers Selective beta1-blocker betaxolol (Betoptic) Nonselective beta1- and beta2-blockers carteolol (Ocupress) levobunolol (Betagan Liquifilm) metipranolol (Optipranolol) timolol (Timoptic, Betimol)

Beta-Adrenergic Blockers (cont’d) Reduce IOP by Reducing aqueous humor formation Increasing aqueous humor outflow Do not affect pupil size, accommodation, or night vision

Beta-Adrenergic Blockers: Indications Reduction of elevated IOP Chronic open-angle glaucoma Ocular hypertension Treatment of some forms of angle-closure glaucoma

Beta-Adrenergic Blockers: Adverse Effects Primarily ocular effects Transient burning and discomfort Blurred vision Pain Photophobia Others Limited systemic effects Headache Dizziness Cardiac irregularities Bronchospasm

Beta-Adrenergic Blockers: Interactions Administration of systemic beta-blockers with high doses of ophthalmic beta-blockers may result in additive effects

Carbonic Anhydrase Inhibitors Available in oral forms for treatment of glaucoma Inhibit the enzyme carbonic anhydrase, which reduces aqueous humor formation in the eye Result is decreased IOP

Carbonic Anhydrase Inhibitors (cont’d) Topical ophthalmic preparations brinzolamide (Azopt) dorzolamide (Trusopt) Oral forms acetazolamide (Diamox) Others

Carbonic Anhydrase Inhibitors: Indications Treatment of glaucoma Open angle Angle closure Preoperatively to reduce intraocular pressure

Carbonic Anhydrase Inhibitors: Adverse Effects Oral forms can produce systemic effects Drowsiness, confusion Transient myopia, tinnitus Anorexia, vomiting, diarrhea Several others Patients with sulfa allergies may develop cross-sensitivities

Osmotic Diuretics Create ocular hypotension by producing an osmotic gradient Water is forced from the aqueous and vitreous humors into the bloodstream Result is reduced volume of intraocular fluid, thus reduced IOP

Osmotic Diuretics (cont’d) Administered IV, PO, or topically Glycerin usually tried first Can cause hyperglycemia Mannitol used if glycerin is unsuccessful Isosorbide and urea may also be used

Osmotic Diuretics (cont’d) Indications Acute glaucoma episodes Before and after ocular surgery to reduce IOP Adverse effects Nausea, vomiting, headache May cause fluid and electrolyte imbalance

Prostaglandin Agonists Newer class of drugs for glaucoma Three drugs latanoprost (Xalatan) Most popular travoprost (Travatan) bimatoprost (Lumigan)

Prostaglandin Agonists (cont’d) Reduce IOP by increasing the outflow of aqueous fluid Increase uveoscleral outflow of fluid Used in the treatment of glaucoma Most drugs allow for single daily dosing because of effects lasting for 20 to 24 hours

Prostaglandin Agonists (cont’d) Effects on eye color In some persons with hazel, green, or blue/brown eyes, eye color will change permanently to brown Color change occurs even if medication stopped

Ocular Antimicrobial Drugs Topical and systemic administration Antibacterial Antiviral Antifungal

Ocular Antimicrobial Drugs (cont’d) Topical application may cause transient and local inflammation, burning, and stinging Use of ophthalmic antibiotics with corticosteroids may make it more difficult to rid the eye of infection

Ocular Antibacterial Drugs Aminoglycosides Antibacterial Gentamicin, tobramycin

Ocular Antibacterial Drugs (cont’d) Macrolides Antibacterial Erythromycin, azithromycin, others Erythromycin also is used for prevention of Neisseria gonorrhoeae eye infections in newborns

Ocular Antibacterial Drugs (cont’d) Polypeptides Antibacterial Bacitracin, polymyxin B

Ocular Antibacterial Drugs (cont’d) Quinolones ciprofloxacin (Ciloxan) Four others Sulfonamides sulfacetamide (Bleph-10) Others

Ocular Antifungal Drugs natamycin Used topically to treat Blepharitis Conjunctivitis Keratitis

Ocular Antiviral Drugs ganciclovir (Vitrasert) Treatment of ocular cytomegalovirus (CMV) Administered by surgical implant in the posterior of the eye fomivirsen (Vitravene) Treatment of ocular CMV Administered by intravitreal injection

Ocular Antiviral Drugs (cont’d) trifluridine (Viroptic) Used in the treatment of types 1 and 2 herpes simplex virus (HSV) Applied topically as drops

Ocular Antiinflammatory Drugs NSAIDs ketorolac (Acular) flurbiprofen (Ocufen) Corticosteroids dexamethasone (Decadron, AK-Dex)

Ocular Antiinflammatory Drugs (cont’d) Act on various parts of the arachidonic acid metabolic pathway Reduce the production of various inflammatory mediators As a result, pain, erythema, and other inflammatory processes are reduced

Ocular Antiinflammatory Drugs (cont’d) Applied topically Used to treat various ophthalmic inflammatory conditions Should not be used for minor abrasions or wounds—may suppress the eye’s ability to resist infections

Ocular Antiinflammatory Drugs (cont’d) Used prophylactically after surgery to prevent inflammation and scarring NSAIDs used for symptomatic treatment of seasonal allergic conjunctivitis

Topical Ophthalmic Anesthetics Tetracaine Proparacaine Used to prevent eye pain during Surgery Ophthalmic examinations Removal of foreign bodies or sutures Diagnostic testing and procedures Short-term use only Not for self-administration

Ophthalmic Diagnostic Drugs Atropine sulfate Results in Mydriasis Cycloplegia Used for Ophthalmic examinations Uveitis (which benefits from pupillary dilation)

Ophthalmic Diagnostic Drugs (cont’d) cyclopentolate (Cyclogyl) Causes mydriasis and cycloplegia Used for diagnostic examinations Not used for uveitis

Ophthalmic Diagnostic Drugs (cont’d) Mydriatic-reversal drug dapiprazole (Rev-Eyes) Alpha-adrenergic blocker Used to Reverse the effects of mydriatic drugs Restore normal pupillary function when sustained mydriasis is not desired

Ophthalmic Diagnostic Drugs (cont’d) fluorescein (AK-Fluor) Ophthalmic diagnostic dye Used to Identify corneal defects Locate foreign bodies in the eye

Ophthalmic Antiallergic Drugs Ophthalmic antihistamines Used to treat symptoms of allergic conjunctivitis (“hay fever”) azelastine (Optivar), olopatadine (Patanol), others

Ophthalmic Antiallergic Drugs (cont’d) Used for seasonal allergy symptoms Mast cell stabilizers cromolyn sodium (Crolom) pemirolast (Alamast) Others Decongestants tetrahydrozoline phenylephrine

Lubricants and Moisturizers Artificial tears Over-the-counter products Provide lubrication or moisture for dry or irritated eyes Available in drops or ointment Brand names include: Murine, Nu-Tears, Moisture Drops, Tears Plus

Lubricants and Moisturizers (cont’d) Restasis Ophthalmic form of cyclosporine Immunosuppressant drug Used to treat “dry eyes”

Nursing Implications Assess the patient’s history, including medication history Assess patient’s baseline vital signs and visual acuity, and perform a physical assessment of the eye and surrounding structures Assess for contraindications to specific drugs

Nursing Implications (cont’d) Follow specific guidelines for administration of ophthalmic drugs Avoid touching the eye with the tip of the dropper or container Apply ointments as a thin layer in the conjunctival sac

Nursing Implications (cont’d) When applying eyedrops, have the patient look up to the ceiling, and place the drop in the conjunctival sac Pressure may be applied to the inner canthus for at least 1 minute to reduce systemic absorption of the drug

Nursing Implications (cont’d) If more than one eye medication is ordered, clarify the correct order and intervals for administration If the patient wears contact lenses, check to see if they should be removed during therapy with eye medications

Nursing Implications (cont’d) Provide patient/family education on correct procedures for administration of eye medications

Nursing Implications (cont’d) Monitor for adverse effects Monitor for therapeutic response to therapy