drugsaffectingthegastrointestinalsystem

7/28/2019 DrugsAffectingtheGastrointestinalSystem

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Dru sAffectin theDru sAffectin the

GastrointestinalSystemGastrointestinalSystem

CaiyingYECaiyingYE

Departmentof

Pharmacology,

Department

of

Pharmacology,

SchoolofBasicMedicine,SchoolofBasicMedicine,

PekingUnionMedicalCollegePekingUnionMedicalCollege


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ep c

cersep c

cers

ommon sease nc ence ra e: .

Pathogenesis of ulcers

ggress ve ac ors e ens ve ac ors

Acid e sin Mucus,bicarbonatelayer

Bilesalts Bloodflow,cellrenewal

Drugs(NSAIDs)

H.pylori

rostag an ns

Phospholipid

Freeradicalscavengers


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Mostcommondisorderoftheeso ha us

Characterizedby

regurgitation

of

gastric

contents

intotheesophagus

Occursmostoftenafterameal

Worsewhen

recumbent

Causedbyincompetentloweresophagealsphincter

Foods

that

cause

relaxation

include:

caffeine,

fats,

, ,medications(betaadrenergicblockers,calciumchannelblockers,nitrates)


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EsophagusEsophagus isis notnot equippedequipped toto handlehandle stomachstomach acidacid=>=> scaringscaring

UsualUsual symptomsymptom isis heartburn,heartburn, anan uncomfortableuncomfortable

burningburning sensationsensation behindbehind thethe breastbonebreastbone (MI(MI oftenoftenm s a enm s a en oror

MoreMore severesevere symptomssymptoms:: difficultydifficulty swallowing,swallowing, chestchest

RefluxReflux intointo thethe throatthroat cancan causecause soresore throatthroat


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esophagealesophageal ulcerulcer andand narrowingnarrowing ofof thethe esophagusesophagus(esophageal(esophageal stricture)stricture)

InIn somesome patients,patients, thethe normalnormal esophagealesophageal lininglining oror

epitheliumepithelium maymay bebe replacedreplaced withwith abnormalabnormalarre sarre s ep e umep e um.. ss con oncon on arre sarre s

esophagus)esophagus) hashas beenbeen linkedlinked toto cancercancer ofof thethe

..

PrimaryPrimary treatmenttreatment :: protonproton pumppump inhibitorsinhibitors


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PepticUlcersPepticUlcers

Therapy Purpose

Therapyis

directed

at

en anc ng os e enseor

eliminatingaggressive

. .,

.

.


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DrugsUsed

in

Peptic

UlcersDrugs

Used

in

Peptic

Ulcers

Inhibitorsof

gastric

acid

production

Proton

pump

inhibitors

Gastrinreceptorantagonist

AntiHelicobacterpylori.drugs

Acid PumpAcid Pump


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aluminumhydroxide

magnesiumhydroxide

H2 rece tor anta onists

cimetidine

ranitidine

Muscarinicanta onists

atropine


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DrugsUsed

in

Peptic

UlcersDrugs

Used

in

Peptic

Ulcers

Protonpump

inhibitors

Gastrinreceptor

antagonist

MucosalProtectants

AntiHelicobacterpylori.Drugs


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AntacidsAntacids

General characteristics

Antacids are weak bases that are taken orally

and that partially neutralize gastric acid and

reduce pepsin activity. Antacids reduce the pain associated with ulcers

and may promote healing. High doses are

times daily.


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Magnesium hydroxide (constipation)

um num y rox e

Sodiumbicarbonate


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22

Competitively block the histamine (H2) receptor of

rendering cells less responsive to not only histamine

gastrin.

gastrin stimulated acid secretion.

com lete inhibition has not been shown


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22

Four

FDA

approved:Cimetidine Ta ametRanitidine Zantac amot ne epc Nizatidine AxidRoxatidine


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HH22receptor

antagonistsreceptorantagonists

Therapeutic effects: Promote the healin of astric and

duodenal ulcers

Upper GI bleed [GIB]

May be effective in stress ulcers &

peptic esophagitis


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H2H2receptor

antagonistsreceptorantagonists

Overalllow

drugsaffectingthegastrointestinalsystem

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