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5
PharmacotherapyPrinciplesinOlderAdults
RichardG.Stefanacci
LearningObjective
1.Describethevariousphysiologicalchangesthatoccurintheolderadultthataffectpharmacokinetic
andpharmacodynamicsresponses.
2.Identifyatleastfourdrugsthatareproblematictouseintheolderadult.
3.Discusssafeprescribingpracticesfortheolderadult.
4.Describethebehavioralandpsychologicalsymptomsofdementia.
INTRODUCTION
Whilethesciencegoverningpharmacotherapyinolderadultshaslargelyremainedthesameforthepast
severalyears,whathassignificantlychangedisthecomplexityoftheenvironment.Today,thenumberand
frailtyoftheolderadultpopulationisfar“more”ineverysensethaneverbefore.Thedeliverysystemhas
changed,withproviders nowbeingplaced atriskfor clinical andfinancial outcomes,as well as new
emergingtechnologiesthatareimpactingthedeliveryofcare,forexample,theanalysisofbigdatafrom
electronic medicalrecords, claims, andotherdata sources. Technologyhasalso broughtforward new
therapies, especially for rare diseases as well as the ability to more accurately diagnose and stage
patients.Astrongappreciationoftheseenvironmentalchangesiscriticaltoproducingpositiveoutcomes
frompharmacotherapy(Box5.1).
Olderadultsarethemostpharmacotherapeuticallychallengingpopulationbecauseoftherequirement
totakeintoconsiderationtheiruniquephysiologyandotherfactorsinthefaceoftheneedtotreatmultiple
chronic comorbid conditions as well as managing within the currentcomplexenvironment previously
mentioned.Thiswarrantsanunderstandingofaginganditseffectsonthebody.Someoftheotherfactors
impactingthispopulationincludechangessuchascognitiveandsocialissuesaffectingproperadherence,
resultinginsuboptimaloutcomes.Inaddition,partofthischallengeisthefactthatmanypharmaceuticals
havenotbeentestedinthispopulation.Asaresult,practitionersneedtorelyontheirknowledgeofbasic
principlesofpharmacotherapyandmonitoronanindividualpatientbasis.
This expertise of managing pharmacotherapy in the older adults is crucial given that the older
population is the fastest growing of any age group. The 2016 American Community Survey (ACS)
estimatedthenumberofpeopleintheUnitedStatesaged65andovertobe49.2million.Ofthem,more
than half (28.75 million or 58%) were aged 65 to 74. The 75-to-84 age group share of the older
populationwasaround14.3millionor29%—morethandoublethenumberandproportion(6.3millionor
13%) for those 85 andolder. There were more females thanmalesamongtheolderpopulation(ACS,
2018).ThelatestnumbersavailablefromtheCentersforDiseaseControlandPrevention(CDC)canbe
obtained through the CDCWide-rangingONline Data for Epidemiologic Research (CDCWONDER).
Thisapplicationmakesmanyhealth-relateddatasets,suchasdemographicinformation,availabletoCDC
staff,publichealthdepartments,researchers, andothers.Thedata are meanttohelpwithpublic health
research,decision-making,prioritysetting,programevaluation,andresourceallocation(Table5.1).
AreportfromtheNationalCenterforHealthStatistics,DivisionofVitalStatistics,attheCDCfinds
thatafteraslightincreaseinoveralllifeexpectancyfrom78.7yearsin2011to78.8yearsin2012,life
expectancy is back to 78.7 years. The difference in life expectancy between the white and black
populations was 3.5 years in 2017 (Arias & Xu,2019). While decreasing in frequency, cancer,heart
disease,andstrokeremainsignificanthealthissuesforolderadults,whichisaconcerngiventherisein
obesity.
Box5.1 EnvironmentalChangesAffectingOlderAdults
Demographics
–Increasingnumberofolderadults
–IncreasingfrailtythroughimprovedmanagementofpreviouslyterminalconditionssuchasHIV,
CHF,cancers
HealthSystems
–Morephysiciansemployedbyhealthsystems
–Healthsystemsandprovidersatriskforclinicalandfinancialoutcomes
Technology
–Analyticcapacityofbigdata
–Useofelectronicmedicalrecords
–Useoftelemedicineandconsultativeservices
–Genomicsandadvanceddiagnostics
CHF,congestiveheartfailure.HIV,humanimmunodeficiencyvirus.
Theconsequencesoflongevityareevidencedbytherisingnumberofolderadultslivingwithmultiple
chronic diseases, contributing to disability, frailty, and decline in function and presenting significant
challengesfor medical management(Norris etal., 2008). Accordingtoa recentreport, nearly80% of
Medicare beneficiaries have at least two chronic conditions and more than 60% have at least three
chronicconditions(DuGoffetal.,2014).Expertshaveestimatedthat26%oftheU.S.populationwillbe
livingwithmultiplechronicconditionsby2030(Anderson,2010).Althoughmultimorbidityisnotlimited
toolderadults,itsprevalenceincreasessubstantiallywithage.Inacross-sectionalstudythatincluded1.7
millionpatients inScotland,Barnettandcolleaguesfoundthat30.4% of thepopulationaged45 to64
years,64.9%ofpeopleaged65to84years,and81.5%ofpeopleaged85yearsorolderreportedatleast
twochronicconditions.Thishasledtoanincreaseduseofhealthcareutilization.
Treatingmultipleproblemswithprescriptionaswellasover-the-counter(OTC)medicationscanresult
inadverse drugreactions (ADRs)andinteractionsrelatedtochanges producedbyaging.Problemsof
polypharmacy (the use of an inappropriate amount and combination of medications to treat a host of
medical conditions), improper dosing for an older adult, and a lack of understandingbyadults about
medicationscanleadtosignificantbutpreventableadverseeffects,suchasfalls,fractures,anddelirium.
This chapter discusses basic physiologic changes of aging, proper prescribing principles, and social
conceptspertainingtosafemedicationusefortheolderadult.
BODYCHANGESANDAGING
Everybodyisaffectedbytheagingprocess,althoughhomeostasisisoftenmaintaineddespiteless-thanoptimal functioning of organ systems. Certain systems are more vitally affected by aging and play
significant roles in the pharmacokinetic and pharmacodynamic changes in drug effects. Box 5.2
summarizestheimpactofagingonthepharmacokineticsofdrugs.
Absorption
Older individuals frequently have oropharyngeal muscle dysmotility and altered swallowing of food.
Reductions in esophageal peristalsis and lower esophageal sphincter (LES) pressures are also more
commonintheaged.Delayedmotilityandgastricemptyinghavebeenreportedinsomecases;aswell,the
propulsivemotilityofthecolonisdecreased,whichmayimpactabsorption.Decreasedgastricsecretions
(acid,pepsin) andimpairmentofthemucous–bicarbonatebarrier arefrequentlydescribed intheolder
populationandmayimpactabsorption.Theprolongedtransittimeinthegastrointestinal(GI)tractstill
allowsforadequatedrugabsorption.
Distribution
Musclethatmakesupleanbodytissuedecreasesintheolderadult,shiftingtoincreasedfatstores,and
body water content decreases by 10% to 15% by age 80. Aging results in some reduction in serum
albumin (by approximately 20%), leading to an increase in free drug concentration of drugs such as
warfarin(Coumadin)andphenytoin(Dilantin).
There are two important plasma-binding proteins in drug metabolism: albumin and alpha1-acid
glycoprotein.Albuminhasanaffinityforacidcompoundsordrugssuchaswarfarin,whereasalpha1-acid
glycoprotein binds more readilywithlipophilic andalkalinedrugs suchaspropranolol (Inderal). The
effectsofchronicdisease,nutritionaldeficits,immobility,andage-relatedliverchangescontributetothe
changesinserumproteins.Thesignificanceofdecreasedserumproteinsisrealizedwhenhighlyproteinbound drugs compete for decreased protein-binding sites. The result can be greater levels of free or
unboundcirculatingdrugand,therefore,potentialtoxicity.
Bodymasschangesmayleadtochangesintotalbodycontentofdrugsinolderadults.Awater-soluble
drug(low volumeof distribution [Vd]) is takenup more readily by lean tissue or muscle andattains
higher serumconcentrations inadults withless bodywater or leantissue.Conversely, a lipid-soluble
drugis retained in bodyfat, resulting in a higher Vd for some drugs. Coupled with a decrease or no
changeintotalbodyclearance,thisincreaseinVdcanleadtoincreasedhalf-livesanddrugaccumulation
inolderadults.Forexample,diazepam(Valium)hasahalf-life(t½)ofapproximately20hoursinayoung
adult, but its t½ can exceed 70 hours in the older adult. In addition, some drugs, such as tricyclic
antidepressants (TCAs) and long-acting benzodiazepines, pass more readily through the blood–brain
barrier,causingmorepronouncedcentralnervoussystem(CNS)effects.Olderadultswhoaretreatedfor
depressionandanxietymayexperiencefatigueandconfusionfrom drugtherapybecauseantidepressant
andantianxietyagentsmorereadilycrosstheirblood–brainbarrier.
TABLE5.1
PopulationbyAgeandSex:2012
Note:Detailsmaynotsumtototalsbecauseofrounding.
The U.S. Census Bureau reviewed this data product for unauthorized disclosure of confidential information and approved the disclosure
avoidancepracticesappliedtothisrelease.CBDRB-FY20-027.
Numbersinthousands.Civiliannoninstitutionalizedpopulation.Plusarmedforceslivingoffpostorwiththeirfamiliesonpost.
Source:U.S.CensusBureau,CurrentPopulationSurvey,AnnualSocialandEconomicSupplement,2019.Internetreleasedate:April2020.
Elimination
Theliveristhemajororganofdrugmetabolisminthebody.Withagingcomesadecreaseinbloodflow
andliversize.However,intheabsenceofdisease, functionis maintained.Decreasedsizeandhepatic
blood flow mayslow theclearanceofcertaindrugs,andreduceddosagesmayberequired (Box 5.3).
This is particularly important for drugs with high hepatic extraction ratios. Phase I metabolism,
particularly oxidation, is affected by aging.The result is decreased oxidation of drugs, whichin turn
resultsinadecreasedtotalbodyclearance.PhaseIImetabolismofdrugsbyconjugation,whichpromotes
drugeliminationbybreakingthedrugintowater-solublecomponents,isnotaffectedbyage.
Aftertheliver,thekidneysarethemostimportantorgansfordrugmetabolismandexcretion.Afterage
40,renalbloodflow declinesandtheglomerularfiltrationrate(GFR)drops approximately1% ayear
andaccelerates withadvancingage.Function isusuallymaintained despitedecreased filtrationunless
illnessordiseaseoverstressesthekidney(Kelleher&Lindeman,2003).Inolderadults,drugsexcreted
primarilybythekidneyaregiveninsmallerdoses,orthetimebetweendosesisextended.
Box5.2 SummaryofPharmacokineticChangesCausedbyAging
AbsorptiveChanges
Decreasedbloodflow
IncreasedgastricpH
Delayedgastricemptying
DistributionChanges
Decreasedalbumin
Decreasedleanbodymass
Increasedtotalbodyfat
Decreasedtotalbodywater
MetabolicChanges
Decreasedliverbloodflow
Decreasedlivermass
Decreasedenzymaticactivity
ExcretionChanges
Decreasedglomerularfiltration
Decreasedsecretion
Box5.3 DrugswithReducedHepaticMetabolisminOlderAdults
Amlodipine
Codeine
Diltiazem
Ibuprofen
Meperidine
Morphine
Naproxen
Nifedipine
Phenytoin
Propranolol
Quinidine
Theophylline
Verapamil
Aserumcreatininelevelalonecannotbeusedtoestimaterenalfunctionintheagingpersonbecause
reductionsin leanbodymass resultindecreasedrates of creatinineformation.This, coupled withthe
decreasedGFR,makestheserumcreatinineappearnormal.ItcannotbeassumedthattheGFRisnormal
fromanormalserumcreatininevalue.Themostaccuratemeansofmeasuringrenalfunctionisa24-hour
urinetestforcreatinineclearance;however,thisisnotstandardprocedurebeforeorderingamedication.
When there is a need to determine a drug choice in the setting of a potential reduction in creatinine
clearance, the Cockcroft-Gault or the Modification of Diet in Renal Disease (MDR) equation (see
Chapter2)isused,whichprovidesanestimatebasedonage,weight,andserumcreatininelevelwithan
adjustmentforsex.Table5.2listsdrugseliminatedbythekidneyandrecommendeddosageadjustments
basedonestimatedcreatinineclearance.
PHARMACODYNAMICCHANGESINTHEOLDERADULT
Many of the changes that occur due to aging affect major organ systems and therefore affect the
pharmacokineticdispositionofthedrug.However,theclinicianalsomustconsidertheimpactdrugshave
ontheagingbody:thepharmacodynamiceffect.Althoughfewpiecesofdataareavailableregardingagerelatedpharmacodynamicchangesinolderadults,itisknownthattheolderadultmaybemoresensitive
to drug– receptor interactions, because of either increased sensitivity of the receptor to the drug or
decreasedcapacitytorespondtodrug-inducedinnervationofreceptors.Inaddition,thenumberoraffinity
ofreceptorsmaybereduced.Nevertheless,itiscommonlyacceptedthattheCNSeffectsofdrugsappear
tobeexaggeratedintheolderpatient.Particularlyegregiousaretheagentswithanticholinergiceffects,
suchastheTCAs,antihistamines,andantispasmodics.Theanticholinergiceffectinducedbytheseagents
can lead to excessive dry mouth, blurred vision, constipation, and even an exacerbation of benign
prostatichyperplasiainmen.Cautionshouldbeusediftheseagentsareprescribedatall.
Similarly, thesedative effectsofagentsmaybe intensifiedinolderadults.Thebenzodiazepinesand
potent analgesic agents are examples of drugs to which older adults are particularly susceptible.
Overprescribing,ortypicalprescribingwithoutconsideringthepotentialforexaggeratedeffect,canlead
tooversedationandagreaterriskoffallsandfractures.
The cardiovascular system also canbe affectedbychangesdue toaging.Orthostatic hypotensionis
more commonin theolderadultbecause of a loss of the baroreceptor reflexandchangesincerebral
bloodflow.Moreover,drugsthatlowerbloodpressureordecreasecardiacoutputputtheolderpatientat
riskforasyncopalepisode.
POLYPHARMACY
Polypharmacyisasignificantfactorinthemorbidityandmortalityofolderadults.Increasingageputsthe
person at risk for multiple chronic illnesses, many of which require drug therapy For example,
osteoarthritis(OA)isthemostcommonjointdisorderintheUnitedStates.SymptomatickneeOAoccurs
in10%ofmenand13%ofwomenaged60yearsorolder.Thecostsintermsofmorbidityarestaggering
(Zhang&Jordan,2010).Chronicstiffnessandpainfromarthritishaveanimpactonfunction,prompting
theroutineuseofnonsteroidalantiinflammatorydrugs(NSAIDs)andaspirinproducts.Long-termuseof
NSAIDs lowers the prostaglandin level in the GI tract, which may result in esophagitis, peptic
ulcerations,GIhemorrhage,andGIperforation.Inanolderadult,treatmentwithhistamine-2blockersor
protonpumpinhibitorstorelievethesideeffectsofaspirinorotherNSAIDsmaycauseadditionalside
effects, such as confusion and mental status changes, which in turn require more treatment. This
demonstrateshoweasilyadverseeventsoccurandsnowballinanolderpatient.ADRsaccountfor30%
of hospital admissions for persons older than age 65; approximately 106,000 deaths are attributed to
medicationproblems.Sadly,15%to65%oftheseeventsarepreventable(Nairetal.,2016;Shiyanbola
&Farris,2010)byavoidingpotentiallyinappropriatemedications,effectivecommunication,andpatient
education.
TABLE5.2
ExamplesofDoseAdjustmentsBasedonEstimatedCreatinineClearance
*DoseadjustmentsbasedonactualcreatinineclearanceorcreatinineclearanceestimatedbytheCockcroft-Gaultformula(seeChapter2).t
Thesedrugsarebestmonitoredusingactualdruglevels,anddoseadjustmentsshouldbemadebasedontheseresults.
*Basedonmanufacturer’sinformation.
Several factors contribute to polypharmacy. Among them are the varied symptoms and complaints
associatedwithmultiplechronicillnesses.Inaddition,adultsoftenbelievethata“pillwillfixwhatails
them,” and the health care provider feels pressured to “prescribe something” to satisfy the patient’s
expectationsofaprescriptionformedication.Whenaparticularmedicationregimenisunsuccessful,the
healthcareprovidertypicallyprescribesanotherdrug;thisisreferredtoastheprescribingcascade.Dr.
Jerry Gurwitz, a noted geriatrician, has warned that “any symptom in an elderly patient should be
considered a drugside effectuntil proved otherwise,”althoughhiswife,LeslieFine,a pharmacist, is
actuallybelievedtohavefirstdescribedthisapproach(Smith,2013).
Polypharmacyis also theeffectfrommanyolderadultsstockpilingtheirdiscontinuedmedicationsin
casetheymaybeneededagain—primarilybecauseofthecostofprescriptiondrugs.Manyproviderswho
visitolderadultsintheirhomeshaveseenevidenceofstockpiledmedications.Someolderadultskeepa
drawerorcabinetfullofoldprescriptiondrugbottles.Somecontainthesamemedication,differingonly
in brand name. Some adults may place a current medication (prescription or OTC) in a labeled
prescription bottle that was used for another drug. In addition, the stockpile may reveal prescription
bottlesforotherfamilymembers.Adultsmaybesharingmedicationsormayhavereceivedmedications
fromotherswhobelievedthatthedrugthathelpedthemwouldhelpthepatient.
Other sources of polypharmacy are “polyproviders.” Manyolder adultssee multiple specialists for
variouschronicdiseases.Medicationsprescribedwithouttheprovidercarefullyreviewingthepatient’s
other medications can lead to drug overuse and complications. Without a primary care provider
overseeingthecareoftheolderadultseeingmultiplespecialists,ADRsaresuretooccur.
Thehealthcareprovidersometimescreatesapolypharmacysituationbecausemultipledrugsareused
to treat several chronic illnesses. The provider who is not astute in the principles of safe geriatric
prescribingpracticesmaycreateavoidablesideeffectsandcomplications.Inaddition,thepatient,who
maybeagreatconsumerofOTCmedicationsorhomeremedies,oftenself-prescribeswithoutknowing
theconsequencesofmixingthesetreatmentswithcurrentprescriptiondrugs.
DrugInteractionsintheOlderAdult
Becauseofnormal,age-relatedphysiologicchanges,theolderadultisatgreaterriskforcomplications
frommedications.Complicationsrelatedtodrug–disease, drug–drug,anddrug–foodinteractionareall
commonlyencountered.(Formoreinformationondrug–druginteractions,seeChapter3.)
AdverseDrugReactions
ADRsoftenresultinsignificantnegativehealthoutcomes,suchasfallsandfractures,costingbillionsof
dollarsinhospitalandnursinghomecare(Shiyanbola&Farris,2010).Althoughageitselfcreatesarisk
forADRs,polypharmacyandthemultiplicityofdrugstakenbyolderadultspresentthegreaterrisk.The
olderadultwithmultiplechronicillnessesandmedicationsmustbeidentifiedasapotentialcandidatefor
ADRs(Ficketal.,2003;Nairetal.,2016).OlderwomeninparticularareatgreatriskforADRsbecause
theyoftenreceivemore prescriptiondrugsandhaveamoresignificantlossofmusclemassthanolder
men.
Thereisapaucityofinformationonsafetyandefficacyofdrugsfortheolderpatient.Mostresearch
andclinicaltrialsareperformed withyoungersubjects.Itoftenisdifficultorimpossibletopredictthe
consequencesofamedicationforitsintendeduseonanolderadultbecausefewpiecesofdatamaybe
available thatspecificallyapplytotheolder population.Inanefforttobetterunderstandtheeffectsof
drugs on older adults, the U.S. Food and Drug Administration (FDA) published guidelines in 1997
recommending thatolder adultsbeincludedinclinical trials ofdrugs specificallybeingdeveloped to
treatprevalentdiseasesaffectingolderadults(Murray&Callahan,2003).
ContributingLifestyleFactors
Preventing adverse events or failed treatments begins with being aware of potential druginteractions
resulting fromolder adultscommonly takingOTC medicationsandprescriptiondrugs without alerting
their health care providers. Additional combinations of foods or nutritional supplements can slow
absorption, prolongingthe time for medications toreach peak levels (see Chapter 3). Fatty foods, in
particular,canincrease intestinal drugabsorptionbecause ofthe longer timerequired to digesta fatty
meal.This,inturn,potentiallyleadstoincreaseddruglevelsortoxicity.
AlcoholandOtherDrugs
Theingestionofalcoholandotherdrugscanalter themetabolismofmanymedicationsinolderadults.
Thecombinationofcomorbidconditions,physiologicalchangeswithage,andconcomitantmedicationsis
often potentiated with alcohol usage. CNS effects such as lethargy and confusion occur, as does
hypotension,when alcohol is combined withnitrates and some cardiovascular drugs. Alcohol can be
foundinmanyOTCproductssuchascoughandcoldsyrupsandmouthwashes.
Alcoholusedisordermaybeoverlookedasapotentialproblem intheolderadult,butabuseamong
community-dwelling(noninstitutionalized) people aged65 andolderhas a prevalence of14% for men
and 1.5% for women. High numbers of older alcoholics are treated in emergency departments and
medical offices orare hospitalized for medical or psychiatric admissions. Depression, whichis more
prevalentintheolderadult,oftencoexistswithalcoholmisuse.Moderatetoheavydrinkersolderthan65
are16timesmorelikelytodieofsuicide.Practitionersneedtobemoreawareofthepotentialforalcohol
misuseinolder adults.Althoughalcohol useandabuse declinewithage,approximately40%ofolder
adultsuse alcohol, withbetween2% and4% meetingthecriteriafor alcoholusedisorder.Theuseof
alcoholisanticipatedtoincreaseasbabyboomersage.Thebabyboomercohorthasahistoryofgreater
alcohol, tobacco, and nonmedical substance usage than previous generations. Life stressors such as
retirement, loss of loved ones, dependency, and chronic illness are contributors to potential alcohol
misuse.Aswell, with11stateslegalizingtherecreational useofmarijuana,itshouldbe expectedthat
olderadultswillalsobeamongtheusers.Sotheinclusionofthispotentialdrug–druginteractionneedsto
betakenintoaccountaswell.
CaffeineandNicotineUse
Caffeine and nicotine are among someof themost commonly used productsthat have the potential to
interactwithcertaindrugs,therebyalteringefficacyandtherapeuticdruglevels.Besidesitspresencein
coffee,tea,andsomesodas,caffeineisfoundinmanyOTCdrugproducts.Theinteractionofcaffeineand
certainmedicationsmayalterdrugabsorption,causeCNSeffects,ordecreasedrugeffectiveness.Table
5.3summarizesselectedcaffeine–medicationinteractions.
Manyolderadultshavelifelongsmokingaddictionsandareunsuccessfulinstoppingthem.Adultsand
providers alike are frequentlyunaware of the effects of nicotine and medications. Nicotine alters the
metabolismofmanydrugs,causesCNSeffects,andinterferes withplateletactivity. Table5.4 reviews
nicotinemedicationeffectsandinteractions.
ADHERENCEISSUES
Onereasonolderadults,similartoallpatients,donotachievetheoptimumoutcomefromtheirtreatments
is their failuretoadheretothemedicationregimen.Inmanycases,prescriptiondrugsarenottakenas
prescribed:Upto40%ofolderadultstaketheirmedicationsimproperly.Morethan40%ofambulatory
adultsaged65andoldertakeatleast5medicationsper week,with12% takingatleast10 per week.
Studieshaveshownthatasthecomplexityofthemedicationregimeincreases,improperdrugusagerises
proportionately.Insomecases,theymaynottakeenoughofthemedication,eitherbecausetheythinkthat
theywillsavemoneybymakingtheprescriptionlastlongerorbecausetheybelievethatthemedicineis
notneededattheprescribeddose.Inothersituations,amedicationmaynotbetakenifitinterfereswith
thepatient’slifestyle,forexample,nottakingadiureticforfearofincontinenceoncertaindays.
TABLE5.3
Medication–CaffeineInteractions
TypeofInteraction ExampleofInteractionEffect
Caffeine-inducedincreasein
gastricacidsecretion
Decreasedabsorptionofiron
Caffeine-inducedgastrointestinal
irritation
Decreasedeffectivenessofcimetidine;increasedgastrointestinalirritationfrom
corticosteroids,alcohol,andanalgesics
Alteredcaffeinemetabolism Prolongedeffectofcaffeinewhencombinedwithciprofloxacin,estrogen,or
cimetidine
Caffeine-inducedcardiac
arrhythmiceffect
Decreasedeffectivenessofantiarrhythmicmedications
Caffeine-inducedhypokalemia Exacerbatedhypokalemiceffectofdiuretics
Caffeine-inducedstimulationof
CNS
Increasedstimulationeffectsfromamantadine,decongestants,fluoxetine,and
theophylline
Caffeine-inducedincreasein
excretionoflithium
Decreasedeffectivenessoflithium
CNS,centralnervoussystem.
TABLE5.4
Medication–NicotineInteractions
TypeofInteraction ExampleofInteractionEffect
Nicotine-inducedalterationin
metabolism
Decreasedefficacyofanalgesics,lorazepam,theophylline,aminophylline,
betablockers,andcalciumchannelblockers
Nicotine-inducedvasoconstriction Increasedperipheralischemiceffectofbetablockers
Nicotine-inducedCNSstimulation Decreaseddrowsinessfrombenzodiazepinesandphenothiazines
Nicotine-inducedstimulationof
antidiuretichormonesecretion
Fluidretentionanddecreasedeffectivenessofdiuretics
Nicotine-inducedincreaseinplatelet
activity
Decreasedanticoagulanteffectiveness(heparin,warfarin);increasedriskof
thrombosiswithestrogenuse
Nicotine-inducedincreaseingastric
acid
DecreasedornegatedeffectsofH2antagonists(cimetidine,famotidine,
nizatidine,ranitidine)
CNS,centralnervoussystem.
CostFactors
Costisactuallybecominglessofanissueforsomeofthemorecommonlyusedmedicationswhileitis
stillanissueforthispopulation,especiallyforolderadultsrequiringinnovativebiologics.Forthemore
commonlyusedmedicationstoday,manyareavailableinagenericformulation,suchasthoseneededfor
hypertension,diabetes,andhypercholesterolemia.TheadditionoftheMedicarePartDprescriptiondrug
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