king saud bin abdulaziz university for health sciences college of

8/14/2019 King Saud Bin Abdulaziz University for Health Sciences College Of

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King Saud Bin Abdulaziz University for Health SciencesKing Saud Bin Abdulaziz University for Health Sciences

College of Nursing and Allied Medical SciencesCollege of Nursing and Allied Medical Sciences

GastrointestinalGastrointestinal And And

Antiemetic Drugs Antiemetic Drugs


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Overview Overview

We will describes drugs used to treat three We will describes drugs used to treat threecommon medical conditions involving thecommon medical conditions involving the

gastrointestinal tract:gastrointestinal tract:peptic ulcerspeptic ulcersgastroesophageal reflux disease (GERD),gastroesophageal reflux disease (GERD),chemotherapy-induced emesis diarrhea andchemotherapy-induced emesis diarrhea andconstipation.constipation.


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Drugs Used to Treat Peptic Ulcer DiseaseDrugs Used to Treat Peptic Ulcer Disease

Infection with gram-negative helicobacterInfection with gram-negative helicobacterpyloripylori

Increased hydrochloric acid secretionIncreased hydrochloric acid secretion

Inadequate mucosal defense againstInadequate mucosal defense againstgastric acidgastric acid


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Treatment Approaches include :Treatment Approaches include :

Eradicating the H. pylori infectionReducing secretion of gastric acid orneutralizing the acid or neutralizing theacid after it is released, and/orProviding agents that protect the gastric

mucosa from damage


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A. Antimicrobial Agents A. Antimicrobial Agents

Optimal therapy for patients with peptic ulcerOptimal therapy for patients with peptic ulcerdisease (both duodenal and gastric ulcers) whodisease (both duodenal and gastric ulcers) who

are infected withare infected with H.H. pylori

pylori , requires antimicrobial, requires antimicrobialtreatment.treatment.

Eradiction of Eradiction of H.H. pylori

pylori results in rapid healing of results in rapid healing of

active peptic ulcers, and low recurrence ratesactive peptic ulcers, and low recurrence rates(less than 15% compared with 60 to 100 % per(less than 15% compared with 60 to 100 % per year for patients with initial ulcers healed by year for patients with initial ulcers healed by traditional antisecretory therapy).traditional antisecretory therapy).


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Effective against nocturnal acidEffective against nocturnal acidsecretion.secretion.

C. HC. H 22 -receptor Antagonists-receptor Antagonists


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Therapeutic Uses:Therapeutic Uses:The use of these agents has decreased with the advent of The use of these agents has decreased with the advent of

the PPIs.the PPIs.

a. Peptic Ulcersa. Peptic Ulcers

All four agents are equally effective in All four agents are equally effective inpromoting healing of duodenal and gastricpromoting healing of duodenal and gastriculcers. However, recurrence is common afterulcers. However, recurrence is common aftertreatment with Htreatment with H 22 antagonists is stopped (60antagonists is stopped (60to 100 % per year).to 100 % per year).


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b. Acute Stress Ulcers b. Acute Stress Ulcers

These drugs are useful in managing acuteThese drugs are useful in managing acutestress ulcers associated with majorstress ulcers associated with majorphysical trauma in high-risk patients inphysical trauma in high-risk patients in

intensive care units. They are usually intensive care units. They are usually injected intravenously.injected intravenously.


the PPIs.the PPIs.


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c. GERDc. GERD

Low doses of HLow doses of H 22 antagonists, recently antagonists, recently released for over-the-counter sale, appearreleased for over-the-counter sale, appearto be effective for prevention andto be effective for prevention and

treatment of heartburn (gastroesophagealtreatment of heartburn (gastroesophagealreflux).reflux).


the PPIs.the PPIs.


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The most common side effects areThe most common side effects areheadache, dizziness, diarrhea andheadache, dizziness, diarrhea and

muscular pain. Other central nervousmuscular pain. Other central nervoussystem effects (confusion, hallucinations)system effects (confusion, hallucinations)occur primarily in elderly patients or afteroccur primarily in elderly patients or afterintravenous administration. Cimetidineintravenous administration. Cimetidinecan also have endocrine effects, because itcan also have endocrine effects, because itacts as a nonsteroidal antiandrogen.acts as a nonsteroidal antiandrogen.


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D. Inhibitors of the HD. Inhibitors of the H ++ /K /K ++ -ATPase Proton-ATPase ProtonPumpPump

Omeprazole [oh MEH pra zole] is the firstOmeprazole [oh MEH pra zole] is the firstclass of a class of drugs that bind to theclass of a class of drugs that bind to theH +/K +-ATPase enzyme system (protonpump) of the parietal cell, thereby suppressing secretion of hydrogen ions

into the gastric lumen. The membrane- bound proton pump is the final step in thesecretion of gastric acid.


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Four Additional PPIs are now Four Additional PPIs are now available:available:

LansoprazoleLansoprazole

EsomeprazoleEsomeprazole


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2. Therapeutic Uses2. Therapeutic Uses

PPIs are superior over the HPPIs are superior over the H 22 antagonistsantagonistsThey are approved for the treatment of GERD.They are approved for the treatment of GERD.

Clinical studies have shown that PPIs reduce theClinical studies have shown that PPIs reduce the

risk of bleeding from an ulcer caused by aspirin andrisk of bleeding from an ulcer caused by aspirin andother nonsteroidal anti-inflammatory agentsother nonsteroidal anti-inflammatory agents(NSAIDS).(NSAIDS).


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G. AntacidsG. Antacids

Antacids are weak bases that react with Antacids are weak bases that react withgastric acid to form water and a salt,gastric acid to form water and a salt,thereby diminishing gastric acidity.thereby diminishing gastric acidity.Because pepsin is inactive at a pH greaterBecause pepsin is inactive at a pH greaterthan 4, antacids also reduce pepticthan 4, antacids also reduce pepticactivity. They may have other actions asactivity. They may have other actions as

well, such as reduction to well, such as reduction to HH .. pyloripylori colonization and stimulation of colonization and stimulation of prostaglandin synthesis.prostaglandin synthesis.


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2. Therapeutic Uses2. Therapeutic Uses

Aluminum- and magnesium- Aluminum- and magnesium-

containing antacids can promotecontaining antacids can promotehealing of duodenal ulcers, buthealing of duodenal ulcers, butevidence for efficacy in the treatmentevidence for efficacy in the treatmentof acute gastric ulcers is lessof acute gastric ulcers is lesscompelling.compelling.


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3. Adverse Effects3. Adverse Effects

Constipating.Constipating.


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These compounds, known asThese compounds, known ascytoprotective compounds.cytoprotective compounds.

1.1. SucralfateSucralfate this complex of aluminum this complex of aluminumhydroxide and sulfated sucrose binds tohydroxide and sulfated sucrose binds topositively charged groups in proteins of positively charged groups in proteins of both normal and necrotic mucosa. both normal and necrotic mucosa.

H. Mucosal Protective AgentsH. Mucosal Protective Agents


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Drugs Used to ControlDrugs Used to ControlChemotherapy-Induced EmesisChemotherapy-Induced Emesis

Although nausea and vomiting may Although nausea and vomiting may

occur in a variety of conditions (foroccur in a variety of conditions (forexample, motion sickness, pregnancy, orexample, motion sickness, pregnancy, orhepatitis). Unpleasant for the patients, ithepatitis). Unpleasant for the patients, itis the nausea and vomiting produced by is the nausea and vomiting produced by

many chemotherapeutic agents thatmany chemotherapeutic agents thatdemand effective management.demand effective management.


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C. Antiemetic DrugsC. Antiemetic DrugsConsidering the complexity of the mechanisms involved in emesis,Considering the complexity of the mechanisms involved in emesis,it is not surprising that antiemetics represents a variety of classesit is not surprising that antiemetics represents a variety of classes

1.1. PhenothiazinesPhenothiazines

The first group of drugs shown to be effectiveThe first group of drugs shown to be effective

antiemetic agentsantiemetic agents

2.2. 2-HT3 Serotonin-receptor blockers2-HT3 Serotonin-receptor blockers


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3.3. Substituted BenzamidesSubstituted BenzamidesMetoclopramide.Metoclop ramide.

The agent of choice.The agent of choice.

4.4. ButyrophenonesButyrophenones

5.5. CorticosteroidsCorticosteroidsDexamethasoneDexamethasone


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ANTIDIARRHEALS ANTIDIARRHEALS

Increased motility of the gastrointestinalIncreased motility of the gastrointestinaltract and decreased absorption of fluidtract and decreased absorption of fluidare major factors of diarrhea.are major factors of diarrhea. Antidiarrheal drugs include anti-motility Antidiarrheal drugs include anti-motility agents, adsorbents, and drugs thatagents, adsorbents, and drugs that

modify fluid and electrolyte transport.modify fluid and electrolyte transport.


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Two drugs that are widely used to controlTwo drugs that are widely used to controldiarrhea are diphenoxylate anddiarrhea are diphenoxylate andloperamide.loperamide.

Antimotility Agents Antimotility Agents


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Adsorbents Adsorbents

Adsorbent agents, such as kaolin and Adsorbent agents, such as kaolin andpectinpectin


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Agents that Modify Fluid and Agents that Modify Fluid andElectrolyte TransportElectrolyte Transport

Experimental and clinical observationsExperimental and clinical observationsindicate that NSAIDs, such as aspirin andindicate that NSAIDs, such as aspirin andindomethacin, are effective in controllingindomethacin, are effective in controllingdiarrhea. This antidiarrheal action isdiarrhea. This antidiarrheal action isprobably due to inhibition of probably due to inhibition of

prostaglandin synthesis.prostaglandin synthesis.


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LAXATIVESLAXATIVES

Laxatives are commonly used toLaxatives are commonly used toaccelerate the movement of food throughaccelerate the movement of food throughthe gastrointestinal tract. These drugsthe gastrointestinal tract. These drugscan be classified on the basis of theircan be classified on the basis of theirmechanism of action as irritants ormechanism of action as irritants or

stimulants of the gut, bulking agents, andstimulants of the gut, bulking agents, andstool softeners.stool softeners.


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Bulking AgentsBulking Agents

The bulk laxatives include hydrophilicThe bulk laxatives include hydrophiliccolloids (from indigestible parts of fruitscolloids (from indigestible parts of fruitsand vegetables). They form gels in theand vegetables). They form gels in thelarge intestine, causing water retentionlarge intestine, causing water retentionand intestinal distension, thereby and intestinal distension, thereby

increasing peristaltic activity.increasing peristaltic activity.


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Surface-active agents that becomeSurface-active agents that becomeemulsified with the stool produce softeremulsified with the stool produce softerfeces and ease passage. These includefeces and ease passage. These includemineral oil and glycerin suppositories.mineral oil and glycerin suppositories.

Stool SoftenersStool Softeners

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