Chapter 81, 82, 83, Peptic Ulcer Dz, Laxatives, and Other GI Drugs including Infectious Dz Flashcards
What is Peptic ulcer dz? Caused by?
Group of upper
gastrointestinal (GI) disorders
Degrees of erosion of the gut
wall
Severe erosion can be
complicated by hemorrhage
and perforation
Imbalance of mucosal and aggressive factors
Most common infx of Peptic ulcer dz?
H. Pylori most common cause of gastric and duodenal ulcers
2nd most common - NSAIDs
Ways anti-ulcer medications work?
Eradicate H. pylori
(antibiotics)
Reduce gastric acidity
(antisecretory agents,
misoprostol)
Enhance mucosal
defenses
(sucralfate, misoprostol)
NSAID induced Ulcer tx considerations?
Proton pump
inhibitors (PPIs) are
preferred
Misoprostol is also
effective but can
cause diarrhea
BLACK BOX
WARNING IN
PREGNANCY
Antacids, sucralfate, &
H2 receptor blockers
are NOT
recommended
What is the preferred tx for NSAID induced Ulcers?
H2 receptor blockers &
PPIs are preferred.
Discontinue NSAIDs if
possible.
What is the tx for H. pylori?
Minimum of 2 antibiotics to reduce risk of resistance developing
CLARITHROMYCIN-BASED TRIPLE
THERAPY 1
CLARITHROMYCIN-BASED TRIPLE
THERAPY 2
BISMUTH-BASED QUADRUPLE
THERAPY
Clarithromycin [Biaxin®] does what for H. pylori infx?
Suppresses growth of H.
pylori by inhibiting protein
synthesis; although rate of resistance is rising
Why is Amoxicillin used for H. pylori?
H/ pyrlori is HIGHLY sensitive to amoxicillin, LOW rate of resistance
Amoxicillin disrupts the cell wall
Antibacterial activity is highest at a neutral pH and thus can be enhanced by reducing gastric acidity with an antisecretory agent
What do bismuth compounds do for H. pyrloi infx?
Act topically to disrupt the cell wall of H. pylori, causing lysis and death
May inhibit urease activity and prevent H. pylori from adhering to the gastric surface
Can impart a harmless black coloration to the tongue and stool
How are tetracyclines used against H. Pylroi?
Inhibitor of bacterial protein synthesis
Highly active against H. pylori
Resistance is rare.
Do not use in pregnant patients and young
children because tetracycline can stain developing teeth.
What is the recommended approximate age that
you can prescribe this drug in children?
> 12 y/o
Metronidazole
[Flagyl®]
Very effective against sensitive strains of H. pylori
Over 40% of strains are now resistant
AVOID ALCOHOL
Disulfiram-like reaction can occur if metronidazole is used with alcohol!
Avoid use during pregnancy
What is the goal of antibiotic regimens for H. pylori? How many abx? What medications can you use with abx? When does eradication occur?
Minimize resistance.
Guidelines recommend 2 antibiotics, preferably 3.
PPI or H2 receptor antagonists
10 days, better with 14 day tx
What is the recommended 1st line choice for treating gastric and duodenal ulcers? Examples?
Histamine 2 Receptor Antagonists by promoting healing by suppressing secretion of gastric acids
Examples:
Cimetidine [Tagamet®]
Ranitidine [Zantac®]
Famotidine [Pepcid®]
Nizatidine [Axid®]
Cimetidine [Tagamet®] A/e? considerations for H. pylori?
Antiandrogenic effects, CNS, pneumonia…
Admin cimetidine and antacids 1 hour apart d/t antacids reducing absorption.
Ranitidine [Zantac®] does what for H. pylori?
more potent, fewer drug a/e compared to cimetidine.
elevation of gastric pH may increase risk of pneumonia
What is th emost effective drug for suppressing secretion of gastric acid?
A proton pump inhibitor (PPI) used for short term GERD, can increase risk of c. diff
Examples - Nexium, Dexilant, Prevacid, Aciphex, Protonix
Omeprazole [Prilosec®] does what?
Inhibit gastric secretion or ulcer prophylaxis, short half life
Major Omeprazole [Prilosec®] a/e?
C. diff
Sucralfate [Carafate®] does what? Drug interactions?
Creates a protective barrier for up to 6 hours for active ulcers and maintenance therapy
DI - antacids
Misoprostol [Cytotec®] is used for what? A/e?
Prevention of gastric uclers caused by NSAIDs
A/e - CONTRAINDICATED DURING PREGNANCY CATEGORY X
Antacid use for gastric ulcers?
React with gastric acid to
produce neutral salts or salts of
low acidity.
Sodium bicarbonate (antacid) does not alter systemic pH
USED WITH CAUTION WITH PATIENTS WHO HAVE RENAL IMPAIRMENT
Common antacid a/e?
Constipation with aluminum, diarrhea with mageniusm, sodium loading
What is Magnesium Hydroxide [Milk of Magnesia] used for?
Rapid high acid neutralizing capacity produces long lasting affects, usually taken with aluminum to promote constipation – can be used as a laxative
CAN CAUSE DIARRHEA
CAUTION W/ RENAL FALURE
Aluminum Hydroxide (Mylanta Maalox® Gaviscon®) can cause? Used with?
Magnesium hydroxide, can cause Constipation
Calcium Carbonate (Tums) can cause what?
Constipation, can be overcome with use of magnesium containing antacids in adjunct
Sodium Bicarbonate is used as?
Useful for treating acidosis
and elevating urinary pH to
promote excretion of acidic
drugs after overdose
Inappropriate for treating
PUD Brief duration, high
sodium content, can cause
alkalosis
Can exacerbate hypertension
and heart failure
Can cause systemic
alkalosis in patients with
renal impairment
Laxative effect vs. Catharsis?
Laxative - mild production of soft forming stool over one or several days
Catharsis - prompt fluid evacuation of the bowel, fast and intense
Contraindications for laxatives?
Abd pain, N/V, cramps, appendicitis, enteritis, diverticulitis, UC, fecal impaction of bowel obstruction, habitual use, in pregnancy or lactation
What is Psyllium?
Psyllium is a fiber
product produced
from the husks used
to increase bulk in
the stool
Bulk-Forming Laxatives: psyllium [Metamucil®]
Fiber that swells with water to form a gel that soften fecal mass, used as temporary tx
Surfactant Laxatives:
docusate sodium [Colace®] produces a stool when?
Several days after onset
Stimulant Laxatives:
bisacodyl [Dulcolax®] ised used specifically for what?
Opioid induced constipation
Osmotic laxatives Milk of Magnesia (MOM) shows effect when?
Low doses - results in 6-12 hours
High doses result in 2-6 hours
Mineral Oil does what? Major A/e?
Lubrication laxative
A/e - Anal leakage
Glycerin suppository is used for?
Useful for reestablishing normal bowel function after termination of chronic laxative use
Purpose of bowel cleansing? Types?
To allow for good visualization of the bowel during a procedure such as a colonoscopy
Sodium phophase - Polythylene glycol + elecs - NASTY TASTING!
Sodium Phosphase Products are used for what and can cause?
Osmotic laxative, Irreversible hyperphosphatemia + renal damage
What can be used as an antiemetic?
Glucocorticoids such as
Methylprednisolone,
Dexamethasone
Commonly used to suppress
chemotherapy-induced
nausea and vomiting (CINV)
Serotonin receptor agenists do what? Major a/e?
Ondansetron [Zofran®]
Block 3 types of serotonin receptors on afferent vagal nerves
A/e.- prolonged QT intervals, risk of torsades de pointes
Aprepitant [Emend®] blocks what?
Blocks neurokinin1-type receptors (for substance P) in the chemoreceptor trigger zone (CTZ) to reduce CINV
Management of CINV? Give when?
Antiemetics are more
effective in preventing
CINV than suppressing
CINV in progress
Give before
chemotherapy drugs
What are first line antiemetics for N/V in pregnancy?
Doxylamine [Unisom®] plus vitamin B6
What is the most effective antidiarrheal agent?
Opioids by activating the opioid receptor in the GI tract
diphenoxylate (plus atropine) [Lomotil®®]]
loperamide [Imodium®®]]
What causes infectious diarrhea?
C. difficile releases toxin A and toxin B tx with oral vancomycin and flagyl
How to treat IBS?
Antispasmodics
Bulk-forming agents
Antidiarrheals
Tricyclic antidepressants
OR
abx and h2 blocker or PPIs
What IBS medication is approved ONLY for women?
Alosetron [Lotronex®]
SEVERE IBS-D lasting > or equal to 6 months and has not responded to conventional tx
What do prokinetic agents do for the GI tract? A/e for longer term therapy?
Metoclopramide [Reglan®]
Suppress emesis and increase upper GI motility!
A/e - irreversible tardive dyskinesia
