Antacids and Anti-ulcer Drugs Flashcards
Which salts are considered to be low-systemic agents? (3)
Aluminum salts
Calcium salts
Magnesium salts
Which salt is considered to be a high-systemic agent?
Sodium salts
What is Simethicone?
A supplemental agent
What is the MOA of antacids?
What byproducts are produced as a result? (3)
They combine with H+ ions.
Water, CO2, Cl-
What are antacids capable of doing at higher doses?
Increase LES tone
Antacids do NOT…
What might be possible as a result?
Do NOT reduce acid secretion or production.
Rebound acid production is possible.
Calcium
Onset:
DOA:
ANC:
Onset: rapid
DOA: long
ANC: very good
Aluminum
Onset:
DOA:
ANC:
Onset: slow
DOA: short
ANC: fair/weak
Magnesium
Onset:
DOA:
ANC:
Onset: rapid
DOA: long
ANC: good
Sodium
Onset:
DOA:
ANC:
Onset: rapid
DOA:short
ANC: fair/good
Simethicone is a…
What does it aid in?
A surfactant - reduces surface tension.
Aids in expulsion of gas.
Adverse effects of Aluminum (4)
Constipation
Hypophosphatemia (can be used acutely for hyperphosphatemia)
Renal osteodystrophy (ESRD)
Encephalopathy
Adverse effects of Magnesium (2)
Diarrhea
Hypermagnesemia
Adverse effects of Calcium (4)
Constipation
Hypercalcemia
Hypophosphatemia (can be used for hyperphosphatemia)
Calcium-based kidney stones
What causes “Milk-Alkali Syndrome”?
Occurs due to hypercalcemia and results in nephropathy and metabolic alkalosis.
Adverse effects of Sodium (3)
Gas
Hypernatremia
Metabolic alkalosis
What are “common, important patient factors” in determining an antacid for a patient? (4)
Dosage form/paliability
Presence of renal or CVD
Electrolyte status
Diseases associated with diarrhea and constipation
Antacids should never be taken…
With another med at the same time.
When should antacids be taken?
1-2 hrs. prior to other meds or 2-4 hrs. after.
MOA of -tidines
H2 receptor antagonists
MOA of -prazoles
Proton pump inhibitors
MOA of Sucralfate
Surface acting agents
MOA of Misoprostol
PGE1 analogs
5 anti-ulcer agent classes
H2 receptor antagonists
PPIs
Surface acting agents
PGE1 analog
Bismuth compounds
All H2 receptor antagonists can be given IV/PO, except _______, which is given only PO.
Nizatidine
MOA of Histamine type-2 blockers
Reversibly inhibit H2-Rs on basolateral membrane of parietal cells
What is the onset of H2-R blockers?
What is the dosing?
When does ulcer healing occur?
What are the adverse effects?
0.5-2 hrs. (longer than antacids, quicker than PPIs)
QD to BID dosing
4-8+ wks.
GI-related (N/D/C) and some CNS related (HA)
What unique adverse effect can occur from Cimetidine?
Decreased testosterone binding to androgen (weak anti-androgen effects)
What is the major drug interaction of Cimetidine?
What is the major drug interaction of Ranitidine?
Prototypical inhibitor of several CYP450 enzymes.
Same, but occurs at approx. 10% of the rate.
What is relative contraindication of H2-R blockers and PPIs?
Pregnancy (if a must, give Ranitidine (H2R antagonist), Lansoprazole (PPI))
All of the PPIs are given PO, except __________, which can be given PO or IV.
Esomeprazole
MOA of PPIs
Covalently bind to SH- groups of H+/K+ ATPase at parietal cell secretory sites, thereby inhibiting gastric acid secretion. After a few days, a new steady-state of pump activity is created.
What is the dosing for PPIs?
How long does it take to achieve full symptom effects?
How long until it heals ulcerations?
QD, effects last approx. 24 hrs.
A few to several days (longer than H2-R antagonists).
4-8+ wks.
What is the major adverse effect of PPIs?
What is the “additional risk”?
GI-related: diarrhea, dyspepsia, nausea.
-C. diff-associated diarrhea
Which PPI is the prototypical PPI for CYP450 inhibition?
Omeprazole
MOA of Sucralfate
What is the major indication for it?
What is the major adverse effect?\
What is the relative contraindication?
How long should they be taken after other meds?
Cross-links via interaction with stomach acid and creates a viscous, sticky polymer that adheres to epithelial cells around the ulcer’s crater.
-Prevents acid access to the ulcer site.
Duodenal ulcers
Constipation (Al(OH)3)
Severe RF
2 hrs. after other meds
Aside from the the typical MOA of Sucralfate, what might also be stimulated?
Local PG and mucous production and EGF (cytoprotection).
MOA of Misoprostol
The standard doses reduces…
It is a PGE1 analog and provides protection to the gastric mucosa and reduces gastric acid release from parietal cells.
- Cytoprotection (stimulates bicarb and mucous production)
- Increases mucosal blood flow
Basal and nocturnal acid output.
What is the indication for Misoprostol?
What is the major adverse effect?
Contraindications? (2)
Prevention of NSAID-induced gastric ulceration in patients with high risk.
GI-related (diarrhea)
Pregnancy, IBD
What is the major action of bismuth compounds?
What was it originally developed as?
Antimicrobial action - believed to prevent microbial attachment, inactivation of enterotoxins and disruption of cell walls
Anti-diarrheal agent
What is the OTC vs. Rx use of bismuth compounds?
OTC - reflux, indigestion and diarrhea
Rx - used in combo with abx and acid suppressant for H. pylori
What are the 2 major adverse effects of bismuth compounds?
What are the Rx interactions?
Constipation
Black (regularly formed) stools
Lots, take 2 hrs. post other meds.
What are the 2 relative contraindications and 2 absolute contraindications for bismuth compounds?
Relative
- antiplatelets and anticoagulants (bismuth subsalicylate)
- severe RF
Absolute
- GI bleeding
- salicylate hypersensitivity
What is the treatment for H. pylori?
Combination therapy is a must: at least 2 abx and an acid reducer (PPI or H2-R blocker)
What is the triple therapy for H. pylori?
What is the dosing and for how long?
PPI
Clarithromycin
Amoxicillin or Metronidazole
BID for 14 days
What is quadruple therapy for H. pylori?
What is the dosing and for how long?
PPI
Metronidazole
Tetracycline
Bismuth subcitrate potassium
PPI at BID, all others at QID for 10-14 days
What is in the Prevpac (BID) for PUD?
Amoxicillin
Clarithromycin
Lansoprazole
What is in the Omeclamox-Pak (BID) for PUD?
Amoxicillin
Clarithromycin
Omeprazole
What is in the Helidac (QID) for PUD?
Bismuth subsalicylate
Metronidazole
Tetracycline
+ PPI
What is in the Pylera (3 capsules QID) for PUD?
Bismuth subcitrate potassium
Metronidazole
Tetracycline
+ PPI (omeprazole)
H. pylori with a PCN allergy, give:
H. pylori with Metronidazole resistance, give:
H. pylori with Clarithromycin resistance, give:
Substitute Metronidazole for Amoxicillin
Substitute Tetracycline
Substitute either Amoxicillin or Tetracycline
Pregnant patients with PUD, but without H. pylori, give:
If moderate?
If severe?
Short courses of antacids or sucralfate
- if moderate, consider ranitidine
- if severe, consider lansoprazole
