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Chapter 11 Drugs for Eyes, Ears, Nose, and Throat © Paradigm Publishing, Inc. 2 Chapter 11 Topics • Anatomy and Physiology of the Eyes, Ears, Nose, and Throat • Glaucoma • Eye Infections • Eye Allergies and Chronic Dry Eye • Retinopathy and Macular Degeneration • Ear Infections • Rhinitis, Seasonal Allergies, and Colds • Herbal and Alternative Therapies © Paradigm Publishing, Inc. 3 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat The Sensory System • Includes organs that produce the five senses: vision, hearing, smell, taste, and touch • Eyes and ears are associated with drug therapy because they are sites of administration for medication Eyes • Sense light and produce vision • Light enters the eye through the pupil and is focused by the lens (located behind the pupil) • Iris (surrounds the pupil) determines eye color and the sclera is the outer coating of the eyeball (white of eye) © Paradigm Publishing, Inc. 4 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Anatomy of the Eye Drugs are used to treat problems in the conjunctiva, anterior chamber, retina, and macula © Paradigm Publishing, Inc. 5 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Sight • Begins with light that travels through the lens to the back of the eye, the retina • In the retina, photoreceptor cells detect light and color • These rod- and cone-shaped cells send signals via the optic nerve to the brain which perceives and interprets sight Rod cells are responsible for night vision and cone cells are responsible for day vision • Inside the macula is the focal point (fovea centralis) on the retina where light is concentrated for vision This part of the retina is rich in cone cells © Paradigm Publishing, Inc. 6 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Other Parts of the Eyes Relevant to Drug Therapy • Cornea Covers the anterior chamber • Anterior chamber Holds aqueous humor, a fluid that lubricates and protects the lens • Vitreous humor Is the fluid inside the eye, behind the lens • Ciliary muscle Holds the lens in place • Conjunctiva Forms the socket that hold the eye in place © Paradigm Publishing, Inc. 7 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Anatomy of the Retina © Paradigm Publishing, Inc. 8 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Ears and Sound • Ears sense sound waves and produce hearing; have three parts: external, middle, and inner • External ear captures sound waves that go through the auditory canal to the tympanic membrane (eardrum) Cerumen (earwax) produced inside the auditory canal • Eardrum Separates the middle ear and external ear Vibrates in response to sound waves, causing the three bones of the middle ear to move • One of the bones taps on the oval window (the entrance to inner ear) © Paradigm Publishing, Inc. 9 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Anatomy of the External, Middle, and Inner Ear © Paradigm Publishing, Inc. 10 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Ears and Sound (continued) • Eustachian tube connects the middle ear to the throat; fluid drains when atmospheric air pressure changes • Inner ear includes the semicircular canals and the cochlea • Fluid in the cochlea responds to tapping on oval window and produces pressure waves • Waves flow through the organ of Corti (spiral-shaped), which is lined with tiny sensory hairs • Vibrations in the hairs send signals to the brain, where sound is perceived and interpreted © Paradigm Publishing, Inc. 11 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Sound Movement through the Inner Ear Strong waves from loud noises break off tiny hairs in the cochlea, causing hearing loss © Paradigm Publishing, Inc. 12 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat URT • Includes the nasal passages, sinuses, back of the throat, pharynx (Adam’s apple), and larynx (voice box) • Includes structures above the trachea (opening to the lungs) Lower respiratory tract includes structures below the trachea • Chemoreceptors in the nose produce the sense of smell • Sinuses and throat are common sites for viral and bacterial infections • A cold and allergies cause symptoms affecting the URT, such as coughing, sinus pain, postnasal drainage, and congestion © Paradigm Publishing, Inc. 13 Anatomy and Physiology of the Eyes, Ears, Nose, and Throat Upper Respiratory Tract © Paradigm Publishing, Inc. 14 Glaucoma About Glaucoma • Is a condition in which abnormally high intraocular pressure pushes on the optic nerve and damages it • Can lead to blindness unless treated • Caused by overproduction of aqueous humor or blockage of its outflow from the anterior chamber • Open-angle glaucoma Is a slowly progressing, chronic condition managed with medication alone • Narrow-angle glaucoma Is an acute condition that comes on quickly and is resolved with surgery followed by drugs © Paradigm Publishing, Inc. 15 Glaucoma Normal Aqueous Humor Flow and Glaucoma © Paradigm Publishing, Inc. 16 Glaucoma Administering Eyedrops • Most eye conditions, especially glaucoma, are treated with topical agents administered directly in the eyes • Ophthalmic drops and the applicator tip must remain sterile so as not to cause infection in the eye • To instill eyedrops, take out contact lenses if wearing them Pull the lower eyelid downward and gently squeeze container for drops to fall into the eye Applicator tip must not touch the eye, eyelid, eyelashes, or fingers © Paradigm Publishing, Inc. 17 Glaucoma Instilling Eyedrops • Most eye drops are solutions • If suspensions, shake well before using © Paradigm Publishing, Inc. 18 Glaucoma Drugs for Glaucoma • Topical beta blockers, alpha receptor agonists, sympathomimetics, miotics, carbonic anhydrase inhibitors, and prostaglandin agonists are given as eyedrops for glaucoma (see Table 11.1) • Beta blockers are first-line therapy • Mechanism of Action (ophthalmic glaucoma agents): reduce aqueous humor production • Mechanism of Action (miotic agents): constrict the pupil slightly by contracting the ciliary muscle Contraction enhances aqueous humor outflow © Paradigm Publishing, Inc. 19 Glaucoma Drugs for Glaucoma (continued) • Dosage Form (most): ophthalmic solution (eyedrops) • Dosage Forms (exceptions): acetazolamide (Diamox) and methazolamide are oral • Side Effects (common): mild stinging, tearing, itchy eyes, and dry eyes • Side Effects (severe): beta blockers can cause systemic effects if enough is absorbed into the bloodstream Slowed heartbeat, heart problems, insomnia, dizziness, vertigo, headaches, tiredness, and difficulty breathing © Paradigm Publishing, Inc. 20 Glaucoma Drugs for Glaucoma: Cautions • If heart or thyroid problems, discuss drug therapy (especially beta blockers ) with prescribers • Prostaglandin agonists can cause the iris of the eye to brown • Oral dosage forms of carbonic anhydrase have several drug interactions and cautions Discuss with prescriber if have kidney or liver problems, diabetes, gout, or asthma • Apply warning label that these products are to be used in the eyes only © Paradigm Publishing, Inc. 21 Eye Infections Conjunctivitis and CMV • Conjunctivitis (“pink eye”) Is inflammation caused by bacteria in the mucous membranes surrounding the eye Symptoms include redness of the sclera and insides of the eyelids, itching, pain, tearing, and release of matter Treat with antibiotics • CMV Is a viral infection of the inner eye that occurs almost entirely in patients with HIV or AIDS Can lead to blindness Treatment involves chronic suppression with antivirals © Paradigm Publishing, Inc. 22 Eye Infections Herpes Viruses • Herpes zoster Is a virus that causes chickenpox and shingles • Herpes simplex Is a virus that causes cold sores • Cause of various problems with the eyes and eyelids • Symptoms include eye pain, redness, cornea cloudiness, tearing, decreased vision, and aversion to bright light • Can cause blindness in serious herpetic viral infections • Treat with topical antiviral agents © Paradigm Publishing, Inc. 23 Eye Infections Administering Eye Ointment • Applying eye ointment Pull the lower eyelid downward Squeeze a continuous ribbon (half-inch) of ointment along the space between the eyeball and lower lid Close the eye for a few minutes to allow ointment to liquefy (vision may be blurry for a few minutes) Gently wipe away excess ointment • Ointments must remain sterile and the applicator tip should not touch the eye or eyelid • Remove contact lenses before applying ointment © Paradigm Publishing, Inc. 24 Glaucoma Applying Eye Ointment Learning to apply eye ointment may take practice © Paradigm Publishing, Inc. 25 Your Turn Question 1: A patient is diagnosed with glaucoma. What drug therapy is the physician likely to order? Answer: Beta blockers are first-line therapy for glaucoma and are used most frequently. Question 2: A patient has a new prescription for an antiviral medication that is an ointment. How will she apply the ointment? Answer: The patient will pull the lower eyelid downward and squeeze a continuous ribbon (half-inch) of ointment along the space between the eyeball and lower lid. Then she will close the eye for a few minutes. She can gently wipe away any excess ointment. © Paradigm Publishing, Inc. 26 Eye Infections Drugs for Eye Infections • Anti-infective agents (see Table 11.2) Include antibiotics and antiviral medications Chosen based on the type of infection and suspected organism Topicals are used unless the infection is systemic • Ophthalmic corticosteroids (see Table 11.3) Are useful for calming inflammation caused by an infection Are used to reduce pain, redness, and irritation, but do not cure the infection © Paradigm Publishing, Inc. 27 Eye Infections Drugs for Eye Infections (continued) • Routes (anti-infectives): most are ophthalmic; antivirals class are IV, oral, intravitreal, and ophthalmic • Routes (ophthalmic corticosteroids): all are ophthalmic except triamcinolone (Triesence, Trivaris) is intravitreal • Side Effects: few and mild • Cautions: many people have allergies to anti-infectives • Apply warning label on all ophthalmic products so that the patient knows they are intended for use in the eyes only and suspensions should have a “shake well” label © Paradigm Publishing, Inc. 28 Eye Allergies and Chronic Dry Eye Drugs for Eye Allergies and Chronic Dry Eye • Eye Allergies Are the exposure to allergens (pollen, dust, smoke, and pollution) that trigger symptoms Symptoms include redness, itching, tearing, and possible conjunctivitis Treatment includes topical antihistamines, NSAIDs, decongestants, mast cell stabilizers (see Table 11.4) Reduce redness and inflammation Ophthalmic NSAIDs also used for pain associated with cataract surgery © Paradigm Publishing, Inc. 29 Eye Allergies and Chronic Dry Eye Drugs for Eye Allergies and Chronic Dry Eye (continued) • Chronic dry eye Is the inability to produce sufficient tears and lubrication for the eye Is a side effect of drugs with anticholinergic effects Treat with normal saline drops or artificial tears first Use cyclosporine if serious, which directly reduces immune activity within the eye • Side Effects (ophthalmic agents): mild stinging or burning • Antihistamines and anti-inflammatories take a few days to work; cyclosporine and mast cell stabilizers take 4 weeks © Paradigm Publishing, Inc. 30 Retinopathy and Macular Degeneration Retinopathy • Is the destruction of the retina • Caused by many conditions; the most common is diabetes • Diabetic retinopathy Tiny blood vessels supplying the retina with blood are damaged and minute hemorrhaging occurs Is a leading cause of blindness in the U.S. Prevent through proper treatment and control of blood glucose levels • Laser treatments for early retinopathy can halt vision loss • Annual eye exams are important for preserving eyesight © Paradigm Publishing, Inc. 31 Retinopathy and Macular Degeneration Macular Degeneration • Is a painless condition that is associated with age and can go undetected until vision is significantly affected • Macula Is responsible for central vision • Dry macular degeneration Is tissue breakdown in the macula occurring with age Symptoms are blurry vision and more light for reading • Wet macular degeneration Is the breakdown of tissue occurring rapidly from fast blood vessel growth and rupture Not associated with age; straight lines appear wavy © Paradigm Publishing, Inc. 32 Ear Infections External and Middle Ear Infections • External ear infection (otitis externa) Is an infection of the ear canal; common in swimmers Bacteria or fungi thrive in moist environments like earwax • Middle ear infections (otitis media) Is most common in children; fluid from the middle ear does not drain well Most are viral and clear on their own Symptoms are ear pain, jaw pain, sinus pain, itching, and fever • Treatment for ear infections is antibiotics © Paradigm Publishing, Inc. 33 Ear Infections Administering Eardrops • Are topical medications effective only for certain infections, such as otitis externa • Middle and inner ear infections require oral drug therapy • Routes: mostly suspensions; also solutions If tubes in ear, use suspension only • Important to keep otic preparations sterile; do not touch tip of applicator to ears or with fingers • Ophthalmic products can be used in the ear • Do not use otic drops in the eyes; painful © Paradigm Publishing, Inc. 34 Dosage Forms and Routes of Administration Otic Administration • Turn the head horizontally • Pull on earlobe and allow drops to fall into ear canal • Remain lying down to allow liquid to coat the ear canal Pull ear up and out for adults © Paradigm Publishing, Inc. Pull ear down and back if under age 3 35 Ear Infections Drugs for Ear Infections • Indications (otic antibiotic preparations): bacterial infections of external ear or middle ear infection if eardrum rupture or ear tubes are present (see Table 11.5) • Indication (drying agents): prevention of external ear infections, especially for regular swimmers • Indication (earwax removers): cerumen impaction • Indication (topical otic analgesics): severe ear pain associated with infection (see Table 11.6) • Side Effects (all otic products; rare): allergic reactions © Paradigm Publishing, Inc. 36 Ear Infections Ototoxicity • Is damage to the ear from chemical or drug exposure • Can cause hearing loss due to some drugs, such as aminoglycosides Usually temporary if caught early • Symptoms begin as ringing in the ears (tinnitus) and progress to noticeable hearing loss © Paradigm Publishing, Inc. 37 Ear Infections Drugs that Can Cause Ototoxicity • Aminoglycosides • Furosemide • Aspirin and salicylates • Neomycin • Benzodiazepines • NSAIDs • Calcium-channel blockers • Quinine • Cisplatin and some chemotherapy agents • Erythromycin and macrolides • Some HIV antiviral agents • Tricyclic antidepressants • Valproic acid © Paradigm Publishing, Inc. 38 Rhinitis, Seasonal Allergies, and Colds Common Conditions of the URT • Includes rhinitis (runny nose), sinus congestion, pharyngitis (sore throat), laryngitis (loss of voice), and epistaxis (nose bleeding) • Seasonal allergies or the common cold Cause runny nose and nasal congestion Allergies • Symptoms include watery, itchy eyes; sneezing; runny nose; and sinus congestion • Common allergens include dust, pollen, pet dander, and cigarette smoke © Paradigm Publishing, Inc. 39 Rhinitis, Seasonal Allergies, and Colds Allergies (continued) • Cells in the respiratory tract release histamine and other inflammatory mediators • Histamine dilates arterioles, allowing blood contents to leak into the local area WBCs (fight disease and foreign allergens) move to the affected area Causes swelling, mucus production, and soreness • Treatment involves avoiding allergens and use of anti-inflammatory medications Antihistamines and decongestants (for relief) © Paradigm Publishing, Inc. 40 Rhinitis, Seasonal Allergies, and Colds The Common Cold • Can elicit a similar response as allergies • Has no cure because too many virus strains quickly mutate • Treatment is symptom relief Use antihistamines, decongestants, cough suppressants, and mucolytics Help with runny nose, stuffy nose, coughing, and chest congestion © Paradigm Publishing, Inc. 41 Rhinitis, Seasonal Allergies, and Colds Drugs for Rhinitis, Seasonal Allergies, and Colds • Treatment for rhinitis and nasal allergies Are many of the same drugs for common cold symptoms • Indications (antihistamines and nasal corticosteroids): runny nose, watery/itchy eyes, and sneezing • Indications (decongestants): nasal congestion from allergies and cold symptoms of stuffy nose and sinus pain © Paradigm Publishing, Inc. 42 Rhinitis, Seasonal Allergies, and Colds Antihistamines • Indications Symptomatic relief of excess nasal secretions, itching, sneezing, coughing Itching and redness from allergic reactions (such as hives and rashes) Cause sedation which is used for mild insomnia, relaxation before anesthesia Active ingredient in most OTC sleep aids First-generation more sedation than second Motion sickness and Parkinson’s disease © Paradigm Publishing, Inc. 43 Rhinitis, Seasonal Allergies, and Colds Antihistamines (continued) • Mechanism of Action: block histamine (H1) receptors, reducing capillary dilation and leakage • Routes: all are oral; diphenhydramine (Benadryl) is also IM and IV • Dosage: vary widely based on patient age, dosage form, reason for use (see Table 11.8) • Side Effects (common): drowsiness (firstgeneration), dry mouth, and urinary retention © Paradigm Publishing, Inc. 44 Rhinitis, Seasonal Allergies, and Colds Antihistamines (continued) • Side Effects (severe) Do not take with medications that cause drowsiness Do not take alcohol Do not take with urination problems May cause excitation (not drowsiness) in children • Cautions Talk to prescriber if high blood pressure or heart problems Do not give to infants or take if breast-feeding Do not take if have glaucoma or if using MAOIs © Paradigm Publishing, Inc. 45 Rhinitis, Seasonal Allergies, and Colds Decongestants • Indications: sinus congestions and pain caused by common cold, infections, and allergies • Mechanism of Action: stimulate adrenergic receptors which constricts blood vessels and reduces swelling • Dosage: varies based on patient age, dosage form, and reason for use • Side Effects (common): headache, dizziness, lightheadedness, insomnia, nervousness, and nausea • Side Effects (serious): increased blood pressure and fast or irregular heartbeat © Paradigm Publishing, Inc. 46 Rhinitis, Seasonal Allergies, and Colds Decongestants (continued) • Cautions Can cause rebound swelling if used for more than 3 days May worsen congestion after stopping product use Lasts a few days Patients may use product longer than needed Some are OTC but restricted, including pseudoephedrine Limits on quantities purchased and must be 18 years of age © Paradigm Publishing, Inc. 47 Rhinitis, Seasonal Allergies, and Colds Cough Suppressants • Indication: excessive and nonproductive (dry, hacking) coughing • Mechanism of Action: Depress cough reflex in cough center of the medulla in the brain • Side Effects: drowsiness, dizziness, and stomach upset; do not take with alcohol • Cautions: Codeine-derivative cough suppressants are OTC but restricted Limits on quantities purchased © Paradigm Publishing, Inc. 48 Rhinitis, Seasonal Allergies, and Colds Expectorants (Mucolytic Agents) • Indication: productive (wet, mucus-producing) cough • Mechanism of Action: liquefy respiratory secretions to allow them to be cleared easily • Dosage: varies widely based on patient age, dosage form, and reason for use (see Table 11.10) • Side Effects: Stomach upset and headache but are usually rare and mild © Paradigm Publishing, Inc. 49 Your Turn Question 1: What is the difference between prescribing ophthalmic drops and otic drops for ear and eye infections? Answer: Ophthalmic drops can be used in both the ear and eye, but otic drops can only be used in the eyes. Question 2: Why is there no cure for the common cold? Answer: The common cold has no cure because there are too many virus strains that quickly mutate. © Paradigm Publishing, Inc. 50 Rhinitis, Seasonal Allergies, and Colds Topical Nasal Corticosteroids • Indications: Nasal allergy symptoms localized to the URT (i.e., nasal passages) • Mechanism of Action: reduces inflammation and allergy symptoms • Route: intranasal • Administration Patient is upright, head tilted slightly forward Insert sprayer tip into nostril, then depress applicator to deliver metered dose Breathe gently and slowly when depressing © Paradigm Publishing, Inc. 51 Rhinitis, Seasonal Allergies, and Colds Topical Nasal Corticosteroids (continued) • Side Effects (common): cough, sore throat, headache, runny nose, and nosebleeds, especially in children • Cautions Shake product well before administration Prime spray application bottle when new and when it has not been used for a while Pump the sprayer a few times until an even amount of spray exists the applicator © Paradigm Publishing, Inc. 52 Herbal and Alternative Therapies • Echinacea, zinc, and vitamin C Are taken to boost immune function and fight off cold and flu viruses Standardized regimens have not been proven • Vitamins A (beta carotene), C, E, and zinc May slow disease progression of age-related macular degeneration Ocuvite (brand-name combination product ) Does not cure or prevent macular degeneration Do not take if smoke Do not take if have high risk of certain cancers © Paradigm Publishing, Inc. 53 Summary • Topical beta blockers, alpha agonists, sympathomimetics, miotics, carbonic anhydrase inhibitors, and prostaglandin agonists are given as ophthalmic drops for glaucoma • Numerous antibiotics and antiviral medications are administered as eyedrops and ointments • Eardrops are used most often for external ear infections but can be used for inner ear infections • Antihistamines, decongestants, cough suppressants, and expectorants are used to for symptoms of colds, infections, and allergies © Paradigm Publishing, Inc. 54