Download - Therapeutic Agents for the Eyes, Ears, Nose, and Throat · 2019-05-11 · West Los Angeles College Therapeutic Agents for the Eyes, Ears, Nose, and Throat Chapter 24 1 West Los Angeles

West Los Angeles College

Therapeutic Agents for the Eyes, Ears, Nose, and Throat

Chapter 24

1


The Eyes (Ophthalmic System)

⬤ Eyes link outside world to the mind ⬤ Images translate into impulses that create

lasting memories in the mind ⬤ Three different levels of eye specialists:

➢ Opticians make lenses ➢ Optometrists perform eye exams ➢ Ophthalmologists are medical doctors

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• Muchofthesurgerycurrentlybeingperformedoneyesisbeingdoneusinglasers.

• Opticiansareskilledinmakinglensesthatcompensateforvisionloss,buttheycannotprescribemedications.Optometristsaretrainedtoperformeyeexaminationsandmayprescribecertainmedicationsfortheeye.Ophthalmologistsarephysicianswhotreatmajorconditionsaffectingtheeye,includingperformingeyesurgeries.

• Manyophthalmicagents,particularlyantibioticsandcorticosteroids,arealsocommonlyprescribedforuseintheear,whichisacceptablebecausetheophthalmicpreparationsaresterileandcanbeusedintheear.However,oticpreparationscannotbeusedintheeyebecausetheyarenotsterile;inaddition,thepHandotherqualitiesofoticformulationsmaypotentiallyinjuretheeye.


Anatomy and Physiology of the Eye

⬤ Eyebrows shade eyes from light ⬤ Eyelashes (more than 200) catch debris, keep

eyes moist, and shade the eyes ⬤ Orbit is bony socket that holds the eye ⬤ Eye position is 100 degrees of peripheral

vision

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• Theeyebrowscanalsokeepperspirationfromreachingtheeyes.• Theeyelidshavefourindividuallayers:theouterskin,themuscles,the

connectivetissue,andtheconjunctiva.• Bactericidalagentskillthebacteria,whereasbacteriostaticagentslimit

bacterialgrowth.Drugsthatarebacteriostaticareusedtoassistthebody’simmunesysteminfightingoffthebacteria.


Anatomy and Physiology of the Eye (Cont.)

⬤ Conjunctiva is thin, transparent mucous membrane that covers anterior eyelids and sclera

⬤ Lacrimal gland, in orbit, secretes tear into eye; has ducts to nasal cavity

⬤ Lysozyme is enzyme in tears with antimicrobial properties

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• Thescleraisthewhiteportionoftheeye.


Eye Anatomy

5

From Potter PA, Perry AG: Fundamentals of nursing, ed 8, St Louis, 2013, Mosby.

• Figure24-1showstheanatomyoftheeye.



⬤ Cornea: Transparent cover allows light into the eye ➢ Connective tissue ➢ Covered with thin epithelial layer ➢ No blood vessels: Nourished by aqueous humor

(tissue fluid) and oxygen ➢ Nerve fibers sensitive to pain

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• Thecorneabulgestohelpprovidevisualacuity.



⬤ Choroid coat: Layer inside sclera ⬤ Fovea: Innermost layer where sharpest vision

occurs ⬤ Sclera joins with iris and ciliary body in front of

eye ⬤ Iris: Colored part of eye to filter light

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• Thechoroidcoatcontainsnumerousbloodvesselsthatsupplynutrientstotheothertissuesoftheretina,anditalsocontainspigmentedcellsthatabsorblightandpreventitfrombeingreflectedwithintheeyeball.

• Theirisisthecoloredpartofeyeseenthroughthecornea,whichconsistsofsmoothmusclesthatregulatepupilsize.



⬤ Posterior cavity: Largest space in eye; surrounded by lens, ciliary body, and retina

⬤ Ciliary body: Forms ring around front of eye; holds lens in place

⬤ Vitreous body: Holds shape and form of eye ⬤ Vitreous humor: Nourishes and cleanses eye

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• Whencertainfibersintheeyecontract,thechoroidcoatispulledforward.• Thiscausestheciliarybodytoshorten;thisthickensthelens,allowingtheeye

tofocusoncloseobjects.


The Retina

⬤ Retina: ➢ Thin layer; contains layers of neurons, nerves,

pigmented epithelium, and membranous tissues ➢ Receptor cells responsible for vision

⬤ Six muscles responsible for eye movements

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• Othermusclesopenandclosetheeyeanddilateandconstrictthepupil.


Eye Muscles and Direction of Movement

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• Whatactionsdothefourrectusmusclesperform?(Thesuperiorrectusrotatestheeyeupwardandinward.Theinferiorrectusrotatestheeyedownwardandinward.Themedialrectusrotatestheeyeinward.Thelateralrectusrotatestheeyeoutward.)

• Whatactionsdothetwoobliquemusclesperform?(Thesuperiorobliquerotatestheeyedownwardandoutward.Theinferiorobliquerotatestheeyeupwardandoutward.)


Pupil and Aqueous Humor

⬤ Pupil: ➢ Dilates (mydriasis) when focusing on distant figure

or darkness ➢ Constricts (miosis) in extreme light

⬤ Aqueous humor provides the nutrients and oxygen to maintain lens and cornea

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• Theaqueoushumoralsokeepstheeyemoistsothattheeyemaintainsitsshape.

• Whenfocusingonadistantfigureortryingtoseeinthedark,thepupiloftheeyedilates(mydriasis),allowingmorelighttoenter.Whentheeyeisexposedtoexcessivelight,thepupilconstricts(miosis).


Aqueous Humor

⬤ Aqueous humor: ➢ Accumulates; must be released to maintain

pressure ➢ Canals of Schlemm: Ducts used to release

aqueous humor ⬤ Retina contains nerve endings to transmit

electrical impulses to brain

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• Aftertheaqueoushumormovesacrossthelens,throughthepupil,andintotheanteriorchamber,itdrainsoutoftheeyethroughsmallopeningsnearthescleraandcornea.


Vision

⬤ Retina contains rods and cones responsible for vision

⬤ Rods: Sight in dim light; produce black and white images

⬤ Cones detect color ⬤ Rods and cones synapse with nerve endings;

signals sent through optic nerve to brain ⬤ Occipital lobe: Visual interpretation

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• Theeyesfocusincominglightandareresponsibleforsendingnerveimpulses,triggeredbyfocusedlight,tothebrainforinterpretation.


Conditions That Affect the Eye

⬤ New developments/treatments: ➢ Laser surgery to correct vision ➢ Lens implantation used for blindness

⬤ Conditions: Glaucoma, conjunctivitis, congestion of eye, and viral and bacterial infections

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• Lasersurgerycorrectsvisionbychangingtheshapeoftheeye.• Oftheconditionslisted,glaucomaistheonlyonethatisnotcontagious.Name

twoothernoncontagiouseyeconditions.(Colorblindnessandblindnessaretwoothernoncontagiouseyeconditions.)


Allergic Conjunctivitis

⬤ With allergies, eyes become itchy, red, and watery

⬤ Seasonal allergies are most common ⬤ Treatment includes: Avoiding irritants, getting

allergy shots, mast cell stabilizers, antihistamines, and decongestants

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• Manyoftheallergyremediesareover-the-counterdrops.


Drug Treatment for Allergies

⬤ Mast cell stabilizers: Prevent allergy cells from opening and releasing chemicals that cause inflammation

⬤ Solutions, suspensions, and systemic agents ⬤ Antihistamines and decongestants alleviate

symptoms and inflammation ⬤ Corticosteroids relieve inflammation

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• RefertoTable24-2(p.610).


Ophthalmic Inflammation Caused by Infection or Injury

⬤ Corticosteroids are effective treatment ⬤ Forms include solutions, suspensions, and

ointments ⬤ Side effects: Temporary burning sensation,

blurred vision, eye pain, and headaches ⬤ Nonsteroidal antiinflammatory drugs (NSAIDs)

inhibit cyclooxygenase (COX)

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• Theseagentsshouldnotbeusedanylongerthannecessarybecausetheymaycompromisetheeffectivenessoftheimmunesystem,resultinginaslowerrateofhealing.

• Prostaglandinsaredirectlyrelatedtothemechanismsresponsibleforinflammationandthepainassociatedwithit.\

• OphthalmicNSAIDssuchasflurbiprofen(Ocufen)andketoprofen(Acular)areavailableinsolutionformulationsonly.


Bacterial Ophthalmic Infections

⬤ Conjunctivitis, known as “pink eye” ➢ Is common in daycare centers; contagious ➢ Is acute inflammation of the conjunctiva

⬤ Causes: Viral, bacterial, fungal, and allergies ⬤ Symptoms: Inflammation, itching, burning, and

white mucus ⬤ Wash hands and avoid touching the eyes

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• Conjunctivitisisthemostcommoneyeinfectionthataffectschildren.


Drug Treatments for Conjunctivitis

⬤ No treatment for viral infection; antibiotics for bacterial infection

⬤ Antiinfectives: Vidarabine, natamycin, gentamicin, and ciprofloxacin

⬤ Ophthalmic sulfonamides ⬤ Aminoglycosides ⬤ Tobramycin is the generic name for Tobrex, which is an aminoglycoside

ophthalmic preparation.

⬤ Macrolides

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• Patientsarecounseledbythepharmacistinthepropertechniqueforadministeringeyedrops,inparttoavoidcontaminatingthemedication.Inaddition,mostmedicationsshouldnotbeinstilledintotheeyeswhileoneiswearingcontactlenses.Solutionsandointmentsdonotrequireshaking.

• Severalagentscanbeusedtotreatallergicconjunctivitis,suchasmastcellstabilizers,antihistamines,anddecongestants.

• Theprimaryophthalmicagentforsuperficialfungaleyeinfectionsisnatamycin,afungicidalagent.Azithromycinandciprofloxacinareantibacterialagents,whereastrifluridineisanantiviraldrug.


Viral and Fungal Ophthalmic Infections

⬤ Viral: Herpes simplex, keratitis, and viral conjunctivitis ➢ Conditions are more common in those who are

immunocompromised ➢ Side effects: Light sensitivity, stinging, and mild

burning sensation ⬤ Fungal: Primary ophthalmic agent for

superficial fungal eye infections is natamycin

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• Theaimofantiviraltherapyistointerruptoralterthesynthesisofnewvirusesataspecificstepduringreplication.

• Thespecificmethodofactionofnatamycininvolvesdrugbindingtothecellmembraneofthefungus.


Glaucoma

⬤ Pressure within the eyes is higher than normal (intraocular pressure [IOP])

⬤ Two causes: Overproduction of aqueous humor; blocked ducts that drain excess aqueous humor

⬤ Left untreated, causes blindness ⬤ Types of glaucoma include primary, acute

congestive, and chronic simple

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• Whatarethepossiblecausesofglaucoma?(Geneticdefects,certaineyeconditions[suchasuveitis],cataractextraction,andcorticosteroiduseareallpossiblecausesofglaucoma.)

• Xalatanophthalmicshouldbestoredintherefrigeratoruntilopened.• XalatanandLumigancancauseapermanentchangeineyecolor,thickening

anddarkeningofeyelashes,anddarkeningofeyelids.• Fiveclassificationsofdrugscanbeusedtotreatglaucoma:beta-adrenergic

blockers,carbonic-anhydraseinhibitors,cholinergicagonists(miotics),sympathomimetics,andprostaglandinanalogs.


Drug Treatments for Glaucoma

⬤ Beta-adrenergic blockers lower IOP ⬤ Carbonic anhydrase inhibitors ⬤ Miotics reduce IOP ⬤ Sympathomimetics decrease aqueous humor ⬤ Prostaglandin agonists increase outflow of

aqueous humor

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• Itisimportantthatthecorrectglaucomadiagnosisismadebecausethemedicationsareveryspecificintheiractions.

• Thereforeanincorrectdiagnosismeansthatthedrugsprescribedcouldbeineffectiveand/ordangerous.


Miscellaneous Ophthalmic Agents

⬤ Artificial tears bought over the counter (OTC) ⬤ Used to relieve dry eyes, irritation ⬤ Ingredients include sodium chloride, buffers to

adjust pH, and additives to prolong effects ⬤ Dosage form is solution ⬤ Comes in various strengths and combinations

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• Restasishelpsalleviatechronicdryeyescausedbyinflammation.• Allophthalmicpreparationshavethepossibilityofcausingeyeirritation

sincetheyareinstilledintotheeye.• Anagentthatcanbeusedforseveredryeyeiscyclosporine(Restasis)eye

drops.Restasishelpsalleviatechronicdryeyescausedbyinflammation.AgentssuchasartificialtearsarecommonlypurchasedOTCforthetreatmentofdryeye.


The Ears (Auditory System)

⬤ Human ear responsible for hearing, balance, equilibrium, and communication skills

⬤ Ear is composed of three sections: External, middle, and inner

⬤ External ear contains auricle: Composed of cartilage and skin; entrance for sound waves

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• Ifequilibriumisnotmaintainedbetweentheairpressureinsideandoutsidetheear,paincanresult.

• Whenmighttherebeanairpressuredifferencethatwouldrequiretheeustachiantubeintheeartoequilibratethetwopressurelevels?(Changingaltitudeswhentravelinginplanesandcarscancauseapressuredifferencethatwouldrequiretheeustachiantubetoacttoequilibratethem.)

• Thehumanearisnotonlyresponsibleforhearing,butitisalsoresponsibleforbalanceandmaintainingequilibrium.


Anatomy of the Ear

25From Potter PA, Perry AG: Fundamentals of nursing, ed 8, St Louis, 2013, Mosby.


External Ear

⬤ Auditory canal: About 1 inch long; leads to tympanic membrane (eardrum)

⬤ There are two major functions of tympanic membrane: Protection of middle ear from foreign objects; transmission of sounds to middle ear

⬤ Sounds transmitted by vibrations ⬤ Cerumen is wax substance produced by gland

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• Thetympanicmembraneismadeoftissuesimilartoskin.• Thetympanicmembraneisathinmembranethatseparatestheexternalear

fromthemiddleearandisalsoknownastheeardrum.


Middle Ear

⬤ Vibration carried to middle ear ⬤ Cavity (space) contains bony structures

(ossicles): Malleus (hammer), incus (anvil), and stapes (stirrup)

⬤ Ossicles are connected to each other ⬤ Eustachian tube:

➢ Leads to nasopharynx ➢ Equalizes pressure between outside and inside

atmosphere

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• Themalleus,incus,andstapes(pronouncedSTAY-peas)alsoareknownasthehammer,anvil,andstirrup.Thesethreebonesareconnectedtoeachotherandarecollectivelyknownasossicles.

• Whatisthefunctionofthesebones?(Theossiclestransmitsoundwavesfromthemiddleeartotheinnerear.)


Inner Ear

⬤ Stapes continues the transfer of sound to the inner ear

⬤ Fluid-filled cavity called the labyrinth; composed of many components that process and transmit audible sounds via nerve impulses to brain

⬤ There are two areas: Perilymph and membrane division

⬤ Cochlea ⬤ Vestibule ⬤ Semicircular canal

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• Thecochleaiscoiledandhasthreefluid-filledcanalsinwhichsmallhairlikestructuresconnecttothenervethattransfersinformationtothebrain.

• Assoundwavesenterthecochlea,thehairsbendandcreateimpulsesthataretransmittedtothenerve.

• Thevestibuleisresponsibleforequilibriumandbalance,monitoredbyhairlikecellsthatareaffectedbygravitywhenmoved.

• Thisinformationgiveshumansasenseofdirectionandorientation.


Common Conditions Affecting the Ear

⬤ Various conditions affect quality of hearing: Infections, earwax accumulation, damage to eardrum, and genetic defects

⬤ Most infections are viral but may lead to bacterial infection as well

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• Thelackoftreatmentcanleadtohearingloss.• Variousconditionscanaffectthequalityofhearing,includinginfections,

swimmersear,earwaxaccumulation,anddamagetotheeardrum,aswellascongenitaldefectsoftheanatomyoftheear.

• DebroxandCeruminexareusedtoremoveearwax,andPinnacaineisusedforpain.


Otitis Media

⬤ Otitis media is infection of the middle ear associated with inflammation of eustachian tube

⬤ Sore throat can lead to middle ear infection; often seen in children

⬤ For recurrent infections, insertion of small tubes by physicians to drain middle ear

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• Asorethroatcanleadtoamiddleearinfectionbecausetheliningofthemiddleearandthenasopharynxformasinglecontinuousmembranousstructure.


Drug Treatments for Otitis Media

⬤ Antiinfectives: Treat infection ⬤ Antibiotics if infection is severe – Amoxicillin or

trimethoprim-sulfamethoxazole ⬤ Antihistamines, decongestants, and

analgesics treat symptoms

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• Childrenwhohaveexcessiveinfectionsmayneedtohavetubesplacedinthetympanicmembranetoallowdrainage.

• AntipyrineandbenzocainearethegenericnamesforAuralgan.


Cerumen Buildup

⬤ Excessive wax builds up or dries, which impedes hearing quality

⬤ Doctor removes wax buildup ⬤ Irrigation kit includes saline solution and ear

syringe ⬤ Other treatments: Mineral oil, glycerin, or

hydrogen peroxide in the ear to soften the wax

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• Waxisanaturalprotectivebarriertooutsideinfections.• Theexcessiveproductionmayleadtoimpairedhearing.


Drug-Induced Ototoxicity

⬤ Ototoxicity caused by some drugs ⬤ Tinnitus (buzzing or ringing in ears) if

untreated leads to permanent ear damage ⬤ Balance may also be affected ⬤ Prognosis: Some cases reverse themselves;

others cause permanent hearing loss ➢ No treatment once hearing loss has occurred

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• Ototoxicityoccurswhenthereiseardamagefrommedicationswithinthecochlearhaircells.

• Tinnitusisaringingorbuzzingintheears.


Nose and Sinuses

⬤ The upper respiratory system is composed of nose and nasal cavities ➢ Pharynx and larynx

⬤ Cilia: Hairlike structures act as protection for nose

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• Thenosealsofunctionsasthesensoryorganforthesenseofsmellandactsasadrainagesystemfortearsfromtheeye.

• Theeyesandearsareimportantsensoryorgans.Thenosealsofunctionsasthesensoryorganforthesenseofsmellandactsasadrainagesystemfortearsfromtheeye.


Allergic Rhinitis

⬤ Itchy eyes ⬤ Runny nose ⬤ Sneezing ⬤ Congestion ⬤ Postnasal drip

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• MostproductsareOTCforthiscondition.


Bacterial Sinusitis

⬤ Infection of sinuses and inflammation of the nose/nasal passages

⬤ Symptoms: Nasal congestion, nasal discharge, cough, sinus pressure, headache, and fever

⬤ Treatment: Rest and fluids; saline irrigation ⬤ Drug treatment: Antibiotic therapy (amoxicillin,

doxycycline, clarithromycin, azithromycin, and trimethoprim-sulfamethoxazole), analgesics, decongestants, and antihistamines

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• Distinguishingbetweenviralandbacterialsinusitiscanbedifficult.• Becauseviralsinusitisimprovesafter7to10days,adiagnosisofacute

bacterialsinusitisgenerallyismadeifthesesymptomshavecontinuedforlongerthan10daysorifsymptomscontinuetoworsenafter5to7days.

• Acutebacterialsinusitismostcommonlydevelopsasasecondaryinfectionafteraviralinfectionoftheupperrespiratorytract.Symptomsofbacterialsinusitisincludenasalcongestion,nasaldischarge,cough,sinuspressure,headache,andfever.Distinguishingbetweenviralandbacterialsinusitiscanbedifficult.Becauseviralsinusitiswillimproveafter7to10days,diagnosisofacutebacterialsinusitisisgenerallymadeifthesesymptomshavecontinuedforlongerthan10daysorifsymptomshavecontinuedtoworsenafter5to7days.

• Amoxicillinisconsideredfirst-linetherapyforbacterialsinusitisbecauseofitslowcostandnarrowantimicrobialspectrum.


Strep Throat and Tonsillitis

⬤ Abrupt onset of throat pain, fever, and exudate from tonsils

⬤ Antibiotics: Reduce duration/severity of symptoms, incidence of complications, and bacterial transmission

⬤ Treatment: Adequate rest and hydration; saltwater gargles

⬤ Drug treatment: Penicillin, ampicillin, amoxicillin, cephalosporins, macrolides, and clindamycin; analgesics, lozenges, numbing sprays, and pain strips

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• Asnotedpreviously,thereisariskofveryrarecomplicationsassociatedwithsuchinfections,includingrheumaticfeverandglomerulonephritis(aformofkidneydamage).

• Thegoalsofantibiotictreatmentforstrepthroataretoreducethedurationandseverityofsymptoms,reducetheincidenceofcomplications(e.g.,rheumaticfever),andreducethetransmissionofthebacteriatoclosecontacts.

• Antibioticprescriptionsforacuteinfectionsmustbetakenuntilgonetoavoidthedevelopmentofresistantstrains.


Gastroesophageal Reflux Disease

⬤ Occurs when upper sphincter of the stomach relaxes

⬤ Risk factors: Obesity, smoking, and pregnancy ⬤ Full recovery is possible ⬤ Treatment: Avoid trigger foods, raise head of the

bed, and surgery (if medication and diet don't work) ⬤ Drug treatment: Antacids, histamine-2 antagonists,

and proton pump inhibitors (PPIs)

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• Thisallowsacidiccontentsfromthestomachtobackupintotheesophagus,whichcanresultinaburningsensationinthechestorthroat.

• Ifleftuntreated,gastroesophagealrefluxdisease(GERD)canresultinsignificantdamagetothethroat.

• AvoidingfoodsthatbringaboutsymptomsofGERDisanimportantaspectoftreatment.Inadditiontoantacids,H

2-antagonistsandPPIsareusedtotreat

GERD.AllthreeclassesofthesemedicationsareavailableOTC,butsomeH2-

antagonistsandPPIsrequireaprescription.• Protonpumpinhibitors(PPIs)areatypeofagentusedforthetreatmentof

GERD.• AllthreemedicationsareavailableOTCandbyprescription.Theusualdose

ofPrevacidis15to30mgeveryday(qd),Prilosecis20mgqd,andZantacis150mgtwicedaily(bid).AlthoughPrilosecandPrevacidneedtobetakenbeforemeals,Zantaccanbetakenwithoutregardtomeals.

Download - Therapeutic Agents for the Eyes, Ears, Nose, and Throat · 2019-05-11 · West Los Angeles College Therapeutic Agents for the Eyes, Ears, Nose, and Throat Chapter 24 1 West Los Angeles

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