GI- Pharmacology- Drugs impacting Acid and H. Pylori Flashcards
What is the most useful tool in diagnosing GERD?
patient history
Other than patient history, what are 2 other diagnostic tests for GERD?
endoscopy
ambulatory esophageal pH test
How can we distinguish GERD from heart attack?
in GERD: Symptoms do not worsen with physical activity
in Heart attack: precipitatio of pain by exertion
What population of people tend to have GERD?
asthmatics
Proton pump inhibitors typically end with what suffix?
-prazole
What is the common suffix for H2 receptor antagonists?
-tidine
What are the 4 single agent antacids (acid neurtalizers)?
aluminum and magnesium hydroxide
calcium carbonate and sodium bicarbonate
What are the mixed antacid preparations and why are they mixed?
They are mixed to prevent diarrhea and constipation as calcium carbonate aluminum hydroxide causes constipation and magnesium hydroxide causes diarrhea
omeprazole, esomeprazole, lansoprazole are the 3 main:
PPIs
Describe the MOA of PPIs:
MOA: Prodrugs that are activated in environment. bind to and irreversibly inhibits the parietal cell H+/K+-ATPase proton pump
acidic
Covalently
Why are the pharmacokinetics of PPIs longer in duration <3 days and what are the pregnancy recommendations?
because they irreversibly covalently bind and no adequate studies for pregnant women
What are the indications for PPIs?
Peptic Ulcer Disease,
Gastroesophageal reflux disease,
esophagitis,
gastric hypersecretion,
gastritis
What is the first and second line treatment for GERD?
PPIs then H2 receptor antagonists
What are some adverse side effects for PPIs and some considerations for long-term therapy?
• Adverse Side effects • Common:
• Headache, abdominal pain, nausea, vomiting, diarrhea, and flatulence
• Considerations for Long-term therapy
- Vitamin B12 deficiency (monitor every 1 to 2 years)
- Hypomagnesemia
- Osteoporosis-related fractures – reduced calcium absorption
- Clostridium difficile infections
- Acute and Chronic Kidney Disease – subclinical acute interstitial nephritis
- Community acquired pneumonia
- Need to taper to avoid acid rebound hypersecretion
Why does one need to taper used of PPIs?
to avoid acid rebound hypersecretion
What is a consideration about other medications and medicines that reduce gastric acid?
• Have patient take other medications 2 hours prior
PPIs decrease the effectivness of which drug?
clopidogrel
PPIs decrease the absorption of which 4 medicines/supplements?
- Cephalosporin antibiotics
- Vitamin B12
- Ketoconazole
- Iron salts
PPIs increase levels of which 2 medications?
- Digoxin
- Voriconazole
What is the MOA of H2 receptor antagonists and which is the most potent of it’s class?
: Reversibly and competitively inhibit the binding of histamine to the H2 receptor
Famotidine is the most potent of the class
What are the indications for H2 receptor antagonists?
Peptic Ulcer Disease,
Gastroesophageal reflux disease,
esophagitis,
gastric hypersecretion,
gastritis,
indigestion,
heartburn
What ADE is unique about H2 receptor antagonists?
• Tolerance and loss of efficacy occurs with prolonged use (after 4 to 6 weeks)
Which H2 receptor antagonist has the most ASE and what are the 2 main worrisome effects?
cimetidine
1. gynecomastia and impotence due to decreased conversion of testosterone to dihydrotestosterone
unconverted testosterone converted to estrogen instead
- inhibits CYP P450 isoforms
Like PPIs, what should one consider if taking other medications?
Have patient take other medications 2 hours prior to taking H2 Blocker
H2 blockers decrease the absorption of which 4 medications/supplements?
- Atazanavir
- Vitamin B12
- Ketoconazole
- Iron salts
H2 blockers increase the levels of which 2 medicines?
- Warfarin
- Procainamide
Which 3 signalling molecules increase acid secretion and what are there receptors?
Histamine - H2 receptor
Ach - Muscarininc receptor
Gastrin - CCK2 receptor
What is the MOA of acid neutralizers?
Weak bases that neutralize the acid and form salt and water
What are the indications for acid neutralizers?
esophagitis,
indigestion,
heartburn,
calcium prophylaxis treatment for osteoporosis in postmenopausal women
note: not for GERD or PUD
What are the ADEs of the acid neutralizer sodium bicarbonate?
- Flatulence/bloating – CO2 generation
- NaCl absorption can result in fluid retention (caution heart failure and hypertension)
Which acid neutralizer is the fastest reacting?
sodium bicarbonate
Which acid neutralizer has the following ASEs?
- Flatulence/bloating –CO2 generation
- Constipation
- Milk-alkali syndrome (access of calcium and unreacted alkali)
calcium carbonate
- Aluminum hydroxide – Fastest/Slowest reaction • Causes what ASE?
- Magnesium hydroxide – Fastest/Slowest reaction • Causes osmotic diarrhea
slowest reactions
Aluminum hydroxide causes constipation
slowest reactions
Magnesium hyproxide causes osmotic diarrhea
As with other gastric medications, patients should take other medications hours prior to taking Antacid
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