Anti-Ulcer Agents Flashcards
How do you treat clarithromycin resistant H. pylori
substitute either amoxicillin or tetracycline
consider adding bismuth
What are the adverse effects and contraindications of misoprostol
adverse effect: primarily GI and CNS related
contraindication: pregnancy - bc induce labor & IBD- bc diarrhea complication
What is the MOA for misoprostol
A PGE1 analog
provide protection for prostaglandin to gastric mucosa & reduces gastric acid release from parietal cell
==> cytoprotection by increasing mucosal defense ((+) HCO3- & mucous production, increase mucosal blood flow)
standard dose –> reduce basal & nocturnal acid output
What are the adverse effects for sucralfate
what should you do to prevent drug interactions
adverse effect = constipation (Al(OH3))
drug interaction - take 2 hours AFTER other medications to prevent interaction w/ crosslinking
what is Omeclamox-Pak
Combo pack used BID
Amoxicillin 1,000 mg
Clarithromycin 500 mg
Omeprazole 20 mg
What is the MOA for PPIs
Covalently bind to sulfhydryl groups of H/K ATPase at parietal cells secretory sites –> (-) gastric acid secretion by irreversibly inhibiting fxn of “-ase” pumps
- (-) pump-induced egress of gastric acid – take several days to create new steady-state of pump activity
- full effect seen in few-several days
(-) 50-90% acid
ulcerations healed w/i 4-8 wks (if not, test for H. pylori)
what are drug interactions and contraindications for H2 antagonists
drug- cimetidine prototypical (-) of several CYP450 isoenzymes ==> lots of drug interactions!
ranitidine - only 10% CYP450 inhibition
relative contraindication: pregnancy -only if necessary (ranitidine)
what is Helidac
combo pack used QID
Bismuth subsalicylate 525 mg
Metronidazole 250 mg
Tetracycline 500 mg
plus add PPI! (not in the pack)
what are the indications and contraindications for sucralfate
indications: Duodenal Ulcers; but also off-label fo aphthous ulcers, mucositis/stomatitis, radiation proctitis/ulcers (enema), bile reflux gastropathy, etc
contraindications: severe renal failure - avoid Al-containing antacids
What are the indications for misoprostol
indication: prevention of NSAID-induced gastic ulceration in pts at high risk of ulcerations & complications
off-label - w/ or w/o mifepristone (pregnancy termination), alone for cervical ripening, post-partum hemorrhaging
What is the MOA for Sucralfate
=sulfated polysaccharide (an octasulfate of sucrose w/ Al(OH)3 added
- undergo cross-linking from interaction w/ stomach acids, creates viscous, sticky polymer –> adheres to epithelial cells around ulcer’s crater ==> prevent acid access to ulcer site
- might also stimulate prostaglandin & mucous production & epidermal GF ==> cytoprotection
What is the ideal treatment for H. pylori
triple drup regimen 10-14 days
- at least 2 ABx (clarithromycin & amoxicillin or metronidazole)
- and an acid reducer (PPI or H2 blocker)
how do you treat ulcers related w/ pregnancy
short course of antacids or sucralfate
moderate symptoms: ranitidine
severe symptoms: lansoprazole
what is the MOA of H2 antagonists
reversibly (-) H2 receptor on basolateral membrane of parietal cells
relief of GERD symptoms - 0.5-2 hrs
ulcer healing occurs in 4-8 weeks (if doesnt - test for H.pylori)
only (-) 20-50% acid production (depends on dose & duration)
What is prevpac
combo pack, used BID
Amoxicillin 1,000 mg -2 caps
Clarithryomycin 500 mg
Lansoprazole 30 mg
What are drug interactions and contraindications for PPIs
drug interactions - omeprazole - prototypical PPI for CYP450 inhibition –> many drug interactions
contraindications - pregnancy - if necessary give lansoprazole or pantaprazole
How do you treat metronidazole resistant H. pylori
substitute w/ tetracylcine
consider quadruaple therapy (w/ clarithromycin & amoxicillin)
what is the common suffix for PPI’s?
list the drugs and mode of delivery
“-prazole”
Omeprazole (can be combined w/ NaHCO3) (po) - (isomer = Esomeprazole; can be combined w/ Naproxen (po/iv))
Lansoprazole (po) - (isomer = Dexlansoprazole (po))
Pantoprazole (po/iv)
Rabeprazole (po)
What are adverse effects of H2 antagonists
relatively mild, transient, infreq - primarily GI and some-CNS related
rare: (more likely w/ long term, high dose)
- Cimetidine- decrease testosterone binding to androgen receptor ==> gynecomastia in men & galactorrhea in women
- -blood dyscrasia - neutropenia, thrombocytopenia
What is the triple therapy for H. pylori
a PPI
Clarithromycin
Amoxicillin (use if metronidazole resistant) or Metronidazole (use if penicillin allergy)
all BID
What are the indications and contraindications of Bismuth Compounds
indication:
- OTC: reflux (heartburn), indigestion & diarrhea
- Rx: combo w/ ABx & acid suppressant for H. pylori
contraindications:
- Relative: antiplatelets & anticoagulants (bismuth sub_salicylate)_ & severe renal failure
- Absolute: GI bleeding & Salicylate hypersensitivity
What is Pylera
3 capsules QID
Bismuth subcitrate potassium 140 mg
Metronidazole 125 mg
Tetracycline 125 mg
PLUS addition of PPI (omeprazole)
What are adverse effects pertaining to PPIs
GI-related
additional risk - CDAD - clostridium difficile-associated diarrhea - on PPI & get watery diarrhea/malaise
CNS-related
What is the common suffix for H2 receptor antagonists
list the drugs and mode of delivery
“-tidine”
Cimetidine - po/iv
Ranitidine - po/iv
Famotidine - po/iv
Nizatidine - po
how do you treat H. pylori if pt is PCN allergy
substitute amoxicillin w/ metronidazole
consider adding Bismuth
What is the reason for false-negative results when testing for H. pylori
ingestion of bismuth, some antimicrobials & some PPIs w/i 4 weeks bc they can suppress H. pylori
What is the MOA of Bismuth compounds
-prevent microbial attachment to mucosa, possible inactivation of enterotoxins & disruption of bacterial cell wall
pepto-bismol/kaopectate/LOTS of others
also in combo pack for H. pylori
developed as anti-diarrheal agent & well known for its anti-microbial actions
What is quadruple therapy for H. pylori
QID
- Metronidazole
- Tetracycline
- Bismuth Subsalicylate
- PPI (BID)
What should you do if H. pylori is not eradicated w/ metronidazole-containing triple-therapy
use non-metronidazole containing quadruple therapy
(Bismuth, PPI and 2 ABx - non metrodazole)
how do you treat ulcers related to NSAID
if NSAID not required –> D/C NSAID and give acetaminophen
if NSAID required - consider COX-2 NSAID &/or consider PPI/Misoprostol
