Antacids And Anti-ulcer (Segars) Flashcards
What is the duration of which antacids should be used for?
Used only for short-term, temporary relief of mild pain and symptoms associated with PUD/GERD
What are the low-systemic antacids?
High-systemic?
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Aluminum-based
Calcium-based
Magnesium-based
High systemic –> Sodium-based
What is the MOA of antacids?
Combine chemically with H ions –> result in generation of common by-products
DO NOT reduce acid secretion or production
Which antacids have a rapid onset, long DOA, and good to very good acid neutralizing capacity?
Ca and Mg
This supplemental compound is a surfactant that decreases surface tension and aids in expulsion of gas
Simethicone
What is a adverse effect of Al?
What about Mg?
What about Ca?
Na?
Al-Constipation
Mg-Diarrhea
Ca-constipation
Na-Gas/flatulence (“bicarb burp”)
When should you take antacids?
Take all antacids 1-2 hrs before other medications OR 2-4 hrs after other medications
Cimetidine, famotidine, nizatidine and ranitidine are what type of anti-ulcer agent?
H2 receptor antagonists
The “-prazoles” are this type of anti-ulcer agent
PPI
Sucralfate is this type of anti-ulcer agent
Surface acting agent
Misoprostol is this type of anti-ulcer agent
PGE1 analog
What is the MOA of H2 blockers?
Reversibly inhibit H2-receptors on basolateral membrane of parietal cell
What are adverse effects of H2 blockers?
Relatively mild and infrequent but Primarily GI-related (nausea/diarrhea/constipation) and some CNS-related (Drowsiness/headache)
Rare side effects: More likely with long-term high dosing –> Cimetidine decreases testosterone binding to androgen receptor so gynecomastia in men and galactorrhea in women
What is an important drug interaction of H2 blockers? Contraindications?
Cimetidine is the PROTOTYPICAL inhibitor of several CYP450 isoenzymes
Significant renal disease and pregnancy are contraindications
What is the MOA of PPIs?
Covalently bind to sulfhydryl groups of H/K ATPase at parietal cell secretory sites, thereby inhibiting gastric acid secretion by irreversibly inhibiting functioning ‘-ase’ pumps
In addition to diarrhea, what other GI-related adverse effect is associated with PPIs?
CDAD –> Clostridium Difficile-Associated Diarrhea
What is an important drug interaction of PPIs? Contraindications?
Omeprazole is the prototypical PPI for CYP450 inhibition
Severe hepatic disease and pregnancy are contraindications
What is the MOA of Sucralfate?
Undergoes cross-linking from interaction with stomach acid, creating a viscous, sticky polymer which adheres to epithelial cells around ulcer’s crater –> prevents acid access to ulcer sites
What is the MOA of Misoprostol?
PGE1 analog, provides protective PG to gastric mucosa and reduces gastric acid release from parietal cell –> provides cytoprotection by increasing mucosal defenses by stimulating bicarb and mucous production and increase mucosal blood flow
What are indications for misoprostol? Contraindications? Adverse?
Indications –> prevent NSAID-induced gastric ulceration in pts at high risk of ulcerations and complications
Contraindications –> pregnancy, IBD
Adverse –> Primarily GI-related (diarrhea), CNS-related (headache/dizziness)
What is the MOA of bismuth compounds?
Exact mechanism for PUD not precisely delineated. Originally developed as anti-diarrheal agent and most well know for its antimicrobial actions
What is the indication for prescription of bismuth compounds?
Used in combo with Abx and acid suppressant for H pylori
What is an important adverse effect of bismuth compounds? Absolute contraindications?
Black/dark stools
Absolute –> GI bleeding and salicylate hypersensitivity
What type of therapy is required for treating H pylori?
Combo therapy –> At least 2 Abx and an acid reducer (PPI or H2 blocker)
Recommended 10-14 days of triple-drug regiment containing a PPI, clarithromycin and either amoxicillin OR metronidazole
List the components of Helidac and how many doses/day
Bismuth subsalicylate
Metronidazole
Tetracycline
PLUS the extra addition of a PPI or H2 blocker
QID
List the components of Pylera and doses/day
Bismuth subcitrate K
Metronidazole
Tetracycline
PLUS the addition of a PPI (omeprazole)
QID
In treating a pt with H pylori with a penicillin allergy, what should you substitute for amoxicillin?
Metronidazole
In treating a pt with H pylori who has metronidazole resistance, what should you substitute with and consider?
Substitute tetracycline and consider quadruple therapy
In tx a pt with H pylori with clarithromycin resistance, what should you substitute with and consider
Substitute either Amoxicillin or Tetracycline, consider quadruple therapy
How should you tx a pregnant pt without H pylori?
Consider short-course of antacids or sucralfate
If moderate symptoms, consider ranitidine
If severe symtpoms, consider lansoprazole
