Acid-Controlling Drugs
94
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Acid-Controlling Drugs. Hydrochloric Acid. Secreted by parietal cells when stimulated by food Maintains stomach at pH of 1 to 4 Secretion also stimulated by: Large fatty meals Excessive amounts of alcohol Emotional stress. Acid-Related Diseases. - PowerPoint PPT Presentation
Transcript of Acid-Controlling Drugs
Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Acid-Controlling Drugs
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HYDROCHLORIC ACIDSecreted by parietal cells when stimulated
by foodMaintains stomach at pH of 1 to 4Secretion also stimulated by:
Large fatty mealsExcessive amounts of alcoholEmotional stress
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ACID-RELATED DISEASESCaused by imbalance of the three cells of
the gastric gland and their secretionsMost common: hyperacidityLay terms for overproduction of HCl by the
parietal cells:Indigestion, sour stomach, heartburn, acid
stomach
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ACID-RELATED DISEASES (CONT’D)
Peptic ulcer disease (PUD)Gastroesophageal reflux disease (GERD)Helicobacter pylori (H. pylori)
Bacterium found in GI tract of 90% of patients with duodenal ulcers and 70% of those with gastric ulcers
Can be detected by serum antibody testsAntibiotics are used to eradicate H. pylori
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TYPES OF ACID-CONTROLLING DRUGS
Antacids H2 antagonists Proton pump inhibitors
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ANTACIDS: MECHANISM OF ACTION
Neutralize stomach acidPromote gastric mucosal defense
mechanismsSecretion of:
Mucus: protective barrier against HClBicarbonate: helps buffer acidic properties of
HCl
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ANTACIDS: MECHANISM OF ACTION (CONT’D)
Antacids DO NOT prevent the overproduction of acid
Antacids DO neutralize the acid once it is in the stomach
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ANTACIDS: DRUG EFFECTS Reduction of pain associated with acid-
related disorders Raising gastric pH from 1.3 to 1.6 neutralizes
50% of the gastric acid Raising gastric pH 1 point (1.3 to 2.3)
neutralizes 90% of the gastric acid Reducing acidity reduces pain
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ANTACIDSOver-the-counter formulations available as:
Capsules and tabletsPowdersChewable tabletsSuspensionsEffervescent granules and tablets
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ANTACIDS (CONT’D)Used alone or in combination
Aluminum saltsMagnesium saltsCalcium saltsSodium bicarbonate
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ANTACIDS: ALUMINUM SALTS Have constipating effects Often used with magnesium to counteract
constipation Often recommended for patients with renal
disease (more easily excreted) Examples
Aluminum carbonate: BasaljelHydroxide salt: AlternaGELCombination products (aluminum and magnesium):
Gaviscon, Maalox, Mylanta, Di-Gel
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ANTACIDS: MAGNESIUM SALTSCommonly cause diarrhea; usually used
with other drugs to counteract this effectDangerous when used with renal failure—
the failing kidney cannot excrete extra magnesium, resulting in accumulation
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ANTACIDS: MAGNESIUM SALTS (CONT’D)
Examples Hydroxide salt: magnesium hydroxide (Milk of
Magnesia)Carbonate salt: Gaviscon (also a combination
product)Combination products such as Maalox, Mylanta
(aluminum and magnesium)
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ANTACIDS: CALCIUM SALTS Many forms, but carbonate is most common May cause constipation, kidney stones Also not recommended for patients with renal
disease—may accumulate to toxic levels Long duration of acid action—may cause increased
gastric acid secretion (hyperacidity rebound) Often advertised as an extra source of dietary
calciumExample: Tums (calcium carbonate)
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ANTACIDS: SODIUM BICARBONATE
Highly solubleBuffers the acidic properties of HClQuick onset, but short durationMay cause metabolic alkalosisSodium content may cause problems in
patients with HF, hypertension, or renal insufficiency
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ANTACIDS AND ANTIFLATULENTSAntiflatulents: used to relieve the painful
symptoms associated with gasSeveral drugs are used to bind or alter
intestinal gas and are often added to antacid combination products
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ANTACIDS AND ANTIFLATULENTS (CONT’D)
Over-the-counter antiflatulentsActivated charcoalSimethicone
Alters elasticity of mucus-coated bubbles, causing them to break
Used often, but there are limited data to support effectiveness
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ANTACIDS: ADVERSE EFFECTSMinimal, and depend on the compound
usedAluminum and calcium
ConstipationMagnesium
DiarrheaCalcium carbonate
Produces gas and belching; often combined with simethicone
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ANTACIDS: DRUG INTERACTIONSAdsorption of other drugs to antacids
Reduces the ability of the other drug to be absorbed into the body
ChelationChemical binding, or inactivation, of another
drugProduces insoluble complexesResult: reduced drug absorption
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ANTACIDS: DRUG INTERACTIONS (CONT’D)
Increased stomach pHIncreased absorption of basic drugsDecreased absorption of acidic drugs
Increased urinary pHIncreased excretion of acidic drugsDecreased excretion of basic drugs
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ANTACIDS: NURSING IMPLICATIONS
Assess for allergies and preexisting conditions that may restrict the use of antacids, such as:
Fluid imbalances Renal disease GI obstruction Heart failure (HF) Pregnancy
Patients with HF or hypertension should not use antacids with high sodium content
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ANTACIDS: NURSING IMPLICATIONS (CONT’D)
Use with caution with other medications because of the many drug interactions
Most medications should be given 1 to 2 hours after giving an antacid
Antacids may cause premature dissolving of enteric-coated medications, resulting in stomach upset
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ANTACIDS: NURSING IMPLICATIONS (CONT’D)
Long-term self-medication with antacids may mask symptoms of serious underlying diseases, such as cancer or bleeding ulcers
If symptoms remain ongoing, patient should seek medical evaluation
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HISTAMINE TYPE 2 (H2) ANTAGONISTS
Reduce acid secretion All available over the counter in lower dosage
forms Most popular drugs for treatment of
acid-related disorderscimetidine (Tagamet) nizatidine (Axid) famotidine (Pepcid)ranitidine (Zantac)
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H2 ANTAGONISTS: MECHANISM OF ACTION
Block histamine at the (H2) receptors of
acid-producing parietal cellsProduction of hydrogen ions is reduced,
resulting in decreased production of HCl
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H2 ANTAGONISTS: DRUG EFFECT AND INDICATIONS
Drug effectSuppressed acid secretion in the stomach
IndicationsGERDPUDErosive esophagitisAdjunct therapy to control upper GI bleedingPathologic gastric hypersecretory conditions
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H2 ANTAGONISTS: ADVERSE EFFECTSOverall, very few adverse effectsCimetidine may induce impotence and
gynecomastia May cause headaches, lethargy, confusion,
diarrhea, urticaria, sweating, flushing, other effects
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H2 ANTAGONISTS: DRUG INTERACTIONS
cimetidine (Tagamet)Binds with P-450 microsomal oxidase system in
the liver, resulting in inhibited oxidation of many drugs and increased drug levels
All H2 antagonists may inhibit the absorption of drugs that require an acidic GI environment for absorption
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H2 ANTAGONISTS: DRUG INTERACTIONS (CONT’D)
Smoking has been shown to decrease the effectiveness of H2 blockers
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H2 ANTAGONISTS: NURSING IMPLICATIONS
Assess for allergies and impaired renal or liver function
Use with caution in patients who are confused, disoriented, or elderly
Take 1 hour before or after antacidsFor intravenous doses, follow
administration guidelines
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PROTON PUMP INHIBITORS
The parietal cells release positive hydrogen ions (protons) during HCl production
This process is called the proton pumpH2 blockers and antihistamines do not stop
the action of this pump
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PROTON PUMP INHIBITORS: MECHANISM OF ACTION
Irreversibly bind to H+/K+ ATPase enzymeThis bond prevents the movement of
hydrogen ions from the parietal cell into the stomach
Results in achlorhydria—ALL gastric acid secretion is temporarily blockedTo return to normal acid secretion, the parietal
cell must synthesize new H+/K+ ATPase
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PROTON PUMP INHIBITORS: DRUG EFFECT
Total inhibition of gastric acid secretion lansoprazole (Prevacid) omeprazole (Prilosec) rabeprazole (AcipHex) pantoprazole (Protonix) (IV form available) esomeprazole (Nexium)
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PROTON PUMP INHIBITORS: INDICATIONS
GERD maintenance therapyErosive esophagitisShort-term treatment of active duodenal
and benign gastric ulcersTreatment of H. pylori–induced ulcers
Given with an antibiotic
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PROTON PUMP INHIBITORS: ADVERSE EFFECTS
Safe for short-term therapySome approved for long-term therapyAdverse effects uncommon
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PROTON PUMP INHIBITORS: NURSING IMPLICATIONS
Assess for allergies and history of liver disease
Not all are available for parenteral administration
May increase serum levels of diazepam and phenytoin; may increase chance for bleeding with warfarin
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PROTON PUMP INHIBITORS: NURSING IMPLICATIONS
(CONT’D) The granules of pantoprazole capsules may be
given via NG tubes, but the NG tube must be at least 16 g or the tube may become clogged
Capsule contents may be opened and mixed with apple juice, but do not chew or crush delayed-release granules
Proton pump inhibitors often work best when taken 30 to 60 minutes before meals
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OTHER DRUGS
sucralfate (Carafate)misoprostol (Cytotec)simethicone (Mylicon)
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SUCRALFATE (CARAFATE)
Cytoprotective drug Used for stress ulcers, peptic ulcer disease Attracted to and binds to the base of ulcers and
erosions, forming a protective barrier over these areas
Protects these areas from pepsin, which normally breaks down proteins (making ulcers worse)
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SUCRALFATE (CARAFATE) (CONT’D)
Little absorption from the gut May cause constipation, nausea, and dry mouth May impair absorption of other drugs—give other
drugs at least 2 hours before sucralfate Do not administer with other medications Binds with phosphate; may be used in chronic
renal failure to reduce phosphate levels
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MISOPROSTOL (CYTOTEC)Synthetic prostaglandin analogProstaglandins have cytoprotective activity
Protect gastric mucosa from injury by enhancing local production of mucus or bicarbonate
Promote local cell regenerationHelp to maintain mucosal blood flow
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MISOPROSTOL (CYTOTEC) (CONT’D)
Used for prevention of NSAID-induced gastric ulcers
Doses that are therapeutic enough to treat duodenal ulcers often produce abdominal cramps, diarrhea
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SIMETHICONEAntiflatulent drugUsed to reduce the discomforts of gastric or
intestinal gas (flatulence)Alters elasticity of mucus-coated gas
bubbles, breaking them into smaller onesResult is decreased gas pain and increased
expulsion via mouth or rectum
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Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Bowel Disorder Drugs
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DIARRHEA
Abnormal passage of stools with increased frequency, fluidity, and weight, or with increased stool water excretion
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DIARRHEA (CONT’D)
Acute diarrheaSudden onset in a previously healthy personLasts from 3 days to 2 weeksSelf-limitingResolves without sequelae
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DIARRHEA (CONT’D)Chronic diarrheaLasts for more than 3 weeksAssociated with recurring passage of
diarrheal stools, fever, loss of appetite, nausea, vomiting, weight loss, and chronic weakness
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CAUSES OF DIARRHEAAcute Diarrhea Chronic DiarrheaBacterial TumorsViral Diabetes mellitusDrug induced Addison’s disease Nutritional factors Hyperthyroidism Protozoa Irritable bowel syndrome
AIDS
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ANTIDIARRHEALS: MECHANISM OF ACTION
AdsorbentsCoat the walls of the GI tractBind to the causative bacteria or toxin,
which is then eliminated through the stoolExamples: bismuth subsalicylate (Pepto-
Bismol), activated charcoal, aluminum hydroxide, others
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ANTIDIARRHEALS: MECHANISM OF ACTION
(CONT’D)Antimotility drugs: anticholinergicsDecrease intestinal muscle tone and
peristalsis of GI tractResult: slows the movement of fecal matter
through the GI tractExamples: belladonna alkaloids (atropine,
hyoscyamine)
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ANTIDIARRHEALS: MECHANISM OF ACTION
(CONT’D)
Antimotility drugs: opiates Decrease bowel motility and relieve rectal spasms Decrease transit time through the bowel, allowing
more time for water and electrolytes to be absorbed
Reduce pain by relief of rectal spasms Examples: paregoric, opium tincture, codeine,
loperamide (over the counter), diphenoxylate
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ANTIDIARRHEALS: MECHANISM OF ACTION
(CONT’D)Intestinal flora modifiers Probiotics or bacterial replacement drugs Bacterial cultures of Lactobacillus organisms
work by:Supplying missing bacteria to the GI tractSuppressing the growth of diarrhea-causing bacteria
Example: L. acidophilus (Lactinex)
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ANTIDIARRHEALS: ADVERSE EFFECTS
AdsorbentsIncreased bleeding timeConstipation, dark stoolsConfusion, twitchingHearing loss, tinnitus, metallic taste, blue
gums
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ANTIDIARRHEALS: ADVERSE EFFECTS (CONT’D)
AnticholinergicsUrinary retention, hesitancy, impotenceHeadache, dizziness, confusion, anxiety,
drowsiness, confusionDry skin, flushingBlurred visionHypotension, bradycardia
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ANTIDIARRHEALS: ADVERSE EFFECTS (CONT’D)
Opiates Drowsiness, sedation, dizziness, lethargy Nausea, vomiting, anorexia, constipation Respiratory depression Hypotension Urinary retention Flushing
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ANTIDIARRHEALS: INTERACTIONS Adsorbents decrease the absorption of many
drugs, including digoxin, clindamycin, quinidine, hypoglycemic drugs, others
Adsorbents cause increased bleeding time and bruising when given with anticoagulants
Antacids can decrease effects of anticholinergic antidiarrheal drugs
Many other interactions
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ANTIDIARRHEALS: NURSING IMPLICATIONS
Obtain thorough history of bowel patterns, general state of health, and recent history of illness or dietary changes; assess for allergies
Do NOT give bismuth subsalicylate to children or teenagers with chickenpox or influenza because of the risk of Reye’s syndrome
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ANTIDIARRHEALS: NURSING IMPLICATIONS
(CONT’D) Use adsorbents carefully in elderly patients or
those with decreased bleeding time, clotting disorders, recent bowel surgery, confusion
Do not administer anticholinergics to patients with a history of narrow-angle glaucoma, GI obstruction, myasthenia gravis, paralytic ileus, and toxic megacolon
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CONSTIPATIONAbnormally infrequent and difficult passage
of feces through the lower GI tractSymptom, not a diseaseDisorder of movement through the colon
and/or rectumCan be caused by a variety of diseases
or drugs
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LAXATIVESBulk formingEmollientHyperosmoticSalineStimulantPeripherally acting opioid antagonists
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LAXATIVES: MECHANISM OF ACTION
Bulk formingHigh fiberAbsorb water to increase bulkDistend bowel to initiate reflex bowel
activityExamples:
psyllium (Metamucil)methylcellulose (Citrucel)
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LAXATIVES: MECHANISM OF ACTION (CONT’D)
EmollientStool softeners and lubricantsPromote more water and fat in the stoolsLubricate the fecal material and intestinal
wallsExamples:
Stool softeners: docusate salts (Colace, Surfak)Lubricants: mineral oil
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LAXATIVES: MECHANISM OF ACTION (CONT’D)
HyperosmoticIncrease fecal water contentResults in bowel distention, increased
peristalsis, and evacuationExamples:
Polyethylene glycol (PEG)Sorbitol, glycerinLactulose (also used to reduce elevated serum
ammonia levels)
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LAXATIVES: MECHANISM OF ACTION (CONT’D)
SalineIncrease osmotic pressure within the
intestinal tract, causing more water to enter the intestines
Results in bowel distention, increased peristalsis, and evacuation
Examples:Magnesium hydroxide (Milk of Magnesia)Magnesium citrate (Citroma)
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LAXATIVES: MECHANISM OF ACTION (CONT’D)
StimulantIncreases peristalsis via intestinal nerve
stimulationExamples:
senna (Senekot)bisacodyl (Dulcolax)
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PERIPHERALLY ACTING OPIOID ANTAGONISTS
Treatment of constipation related to opioid use and bowel resection therapy
Block entrance of opioid into bowel Strict regulations for use Allow bowel to function normally with continued
opioid usemethylnaltrexone (Relistor)alvimopan (Entereg)
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LAXATIVES: INDICATIONSLaxative Group Use
Bulk forming Acute and chronicconstipation, irritable
bowel syndrome, diverticulosis
Emollient Acute and chronicconstipation, fecal
impaction
Facilitation of BMs in anorectal conditions
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LAXATIVES: INDICATIONS (CONT’D)
Laxative Group UseHyperosmotic Chronic constipation
Diagnostic and surgical preps
Saline ConstipationDiagnostic and surgical preps
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LAXATIVES: INDICATIONS (CONT’D)
Laxative Group UseStimulant Acute constipation
Diagnostic and surgical preps
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LAXATIVES: ADVERSE EFFECTS Bulk forming
ImpactionFluid overloadElectrolyte imbalancesEsophageal blockage
EmollientSkin rashesDecreased absorption
of vitaminsElectrolyte imbalancesLipid pneumonia
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LAXATIVES: ADVERSE EFFECTS (CONT’D)
HyperosmoticAbdominal bloatingElectrolyte imbalancesRectal irritation
SalineMagnesium toxicity (with renal insufficiency)CrampingElectrolyte imbalancesDiarrheaIncreased thirst
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LAXATIVES: ADVERSE EFFECTS (CONT’D)
StimulantNutrient malabsorptionSkin rashes Gastric irritationElectrolyte imbalancesDiscolored urineRectal irritation
All laxatives can cause electrolyte imbalances!
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LAXATIVES: NURSING IMPLICATIONS
Inform patients not to take a laxative or cathartic if they are experiencing nausea, vomiting, and/or abdominal pain
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LAXATIVES: NURSING IMPLICATIONS (CONT’D)
A healthy, high-fiber diet and increased fluid intake should be encouraged as an alternative to laxative use
Long-term use of laxatives often results in decreased bowel tone and may lead to dependency
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LAXATIVES: NURSING IMPLICATIONS (CONT’D)
Patients should take all laxative tablets with 6 to 8 ounces of water
Patients should take bulk-forming laxatives as directed by the manufacturer with at least 240 mL (8 ounces) of water
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LAXATIVES: NURSING IMPLICATIONS (CONT’D)
Give bisacodyl with water because of interactions with milk, antacids, and juices
Monitor for therapeutic effect
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Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Antiemetic and Antinausea Drugs
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DEFINITIONSNausea
Unpleasant feeling that often precedes vomitingEmesis (vomiting)
Forcible emptying of gastric, and occasionally, intestinal contents
Antiemetic drugsUsed to relieve nausea and vomiting
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VOMITING CENTER AND CHEMORECEPTOR TRIGGER
ZONE
Vomiting center (VC)Chemoreceptor trigger zone (CTZ)
Both located in the brainOnce stimulated, cause the vomiting reflex
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ANTIEMETICS AND ANTINAUSEA DRUGS: MECHANISM OF ACTION
Many different mechanisms of actionMost work by blocking one of the vomiting
pathways, thus blocking the stimulus that induces vomiting
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INDICATIONS
Specific indications vary per class of antiemetics
General use for each type: prevention and reduction of nausea and vomiting
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MECHANISM OF ACTION AND OTHER INDICATIONS
Anticholinergic drugs (ACh blockers)Bind to and block acetylcholine (ACh) receptors
in the inner ear labyrinthBlock transmission of nauseating stimuli to CTZ Also block transmission of nauseating stimuli
from the reticular formation to the VCScopolamine
Also used for motion sickness (transdermal patch)
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MECHANISM OF ACTION AND OTHER INDICATIONS (CONT’D)
Antihistamine drugs (H1 receptor blockers)Inhibit ACh by binding to H1 receptorsPrevent cholinergic stimulation in vestibular and
reticular areas, thus preventing nausea and vomitingAlso used for motion sickness, nonproductive cough,
allergy symptoms, sedationdimenhydrinate (Dramamine)diphenhydramine (Benadryl)meclizine (Antivert)
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MECHANISM OF ACTION AND OTHER INDICATIONS (CONT’D)
Antidopaminergic drugsBlock dopamine receptors on the CTZAlso used for psychotic disorders, intractable
hiccupsprochlorperazine (Compazine)promethazine (Phenergan)droperidol (Inapsine): Use is controversial because
of associated cardiac dysrhythmiaOthers
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MECHANISM OF ACTION AND OTHER INDICATIONS (CONT’D)
Prokinetic drugsBlock dopamine in the CTZCause CTZ to be desensitized to impulses it
receives from the GI tractAlso stimulate peristalsis in GI tract, enhancing
emptying of stomach contentsAlso used for GERD, delayed gastric emptyingmetoclopramide (Reglan)
Long-term use may cause irreversible tardive dyskinesia
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MECHANISM OF ACTION AND OTHER INDICATIONS (CONT’D)Serotonin blockers
Block serotonin receptors in the GI tract, CTZ, and VC
Used for nausea and vomiting in patients receiving chemotherapy and for postoperative nausea and vomiting
dolasetron (Anzemet)granisetron (Kytril)ondansetron (Zofran)palonosetron (Aloxi)
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MECHANISM OF ACTION AND OTHER INDICATIONS (CONT’D)
TetrahydrocannabinoidsMajor psychoactive substance in marijuanaInhibitory effects on reticular formation,
thalamus, cerebral cortexAlter mood and body’s perception of its
surroundings
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MECHANISM OF ACTION AND OTHER INDICATIONS (CONT’D)
Tetrahydrocannabinoids (cont’d)dronabinol (Marinol)Used for nausea and vomiting associated with
chemotherapy, and anorexia associated with weight loss in AIDS patients
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ADVERSE EFFECTS
Vary according to drug usedStem from their nonselective blockade of
various receptors
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HERBAL PRODUCTS: GINGER
Used for nausea and vomiting including that caused by chemotherapy, morning sickness, and motion sickness
Adverse effectsAnorexia, nausea and vomiting, skin reactions
Drug interactionsMay increase absorption of oral medicationsIncrease bleeding risk with anticoagulants
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NURSING IMPLICATIONS (CONT’D)
Many of these drugs cause severe drowsiness; warn patients about driving or performing any hazardous tasks
Taking antiemetics with alcohol may cause severe CNS depression
Teach patients to change position slowly to avoid hypotensive effects
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NURSING IMPLICATIONS (CONT’D)
For chemotherapy, antiemetics are often given 30 to 60 minutes before chemotherapy begins
Monitor for therapeutic effectsMonitor for adverse effects
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