GI & Peptic 1 Flashcards
What are the 3 Acid-Peptic Diseases?
- GERD
- Peptic ulcer (gastric & duodenal)
- Stress-related mucosal injury
Over 90% of peptic ulcers are caused by what 2 things?
- Helicobacter pylori
- NSAIDs
What induced this Peptic Ulcer?
- Chronic
- Site of damage: Duodenum
- Depend on Intragastric pH
- Sxs: epigastric pain
- Ulcer depth: superficial
- Less severe GI bleeding, single vessel
H. pylori
What induced this Peptic Ulcer?
- Chronic
- Site of damage: Stomach
- Less dependent on Intragastric pH
- Asymptomatic
- Deep ulcer depth
- More severe GI bleeding, single vessel
NSAID
What inuced this Peptic Ulcer?
- Acute
- Site of damage: Stomach
- Less dependent on Intragastric pH
- Asymptomatic
- Most superficial Ulcer depth
- GI bleeding is more severe (superficial mucosal capillaries)
SRMD
(stress related mucosal disease)
What are the two MOAs of the two drug classes which treat ulcers?
- agents that reduce intragastric acidity
- agents that promote mucosal defense
What medication is used for “Esophageal Clearance” to tx GERD?
Bethanechol
What medication is used for “Gastric Emptying” for tx of GERD?
Metoclopramide
Treatments for “Gastric Acid”
- H2 receptor antagonists
- Proton Pump Inhibitors (PPI)
- Omeprazole
What are the 3 receptors in a Parietal Cell?
- Gastrin (CCK-B)
- Histamine (H2)
- Acetylcholine (muscarinic, M3)
Acid Secretion
Which neurotransmitter is released from vagal postganglionic nerves?
Acetylcholine
What are the 3 agents which reduce Intragastric Acidity?
- Antacids
- H2 receptor antagonists (H2 blockers)
- Proton Pump Inhibitors (PPI)
Which Antacid?
- Reacts rapidly with HCL to produce carbon dioxide & sodium chloride
-
Adverse effects:
- CO2 gastric distention & belching
- Unreacted alkali is readily absorbed, potentially causing metabolic alkalosis when given in high doses or to pts w/ renal insufficiency
- Sodium chloride absorption may exacerbate fluid retenion in pts w/ HF, HTN, & renal insufficiency
Sodium Bicarbonate
What are 2 examples of Sodium Bicarbonate Antacids?
- Baking soda
- Alka seltzer
Which Antacid?
- Less soluble & reacts more slowly w/ HCL to form carbon dioxide & calcium chloride
-
Adverse effects:
- belching or metabolic alkalosis
- excessive doses of either sodium bicarb or calicum carbonate w/ calcium-containing products can lead to hypercalcemia, renal insufficiency, and metabolic alkalosis (milk alkali syndrome)
Calcium Carbonate
What are 2 examples of Calcium Carbonate Antacid
- Tums
- Os-Cal
Adverse Effects of which antacid?
- no gas is generated, belching does not occur
- metabolic alkalosis is also uncommon because of the
- osmotic diarrhea
- constipation
Magnesium hydroxide or Aluminum hydroxide
Antacids should not be given within 2 hours of doses of what 4 medications?
- Tetracycline
- Fluoroquinolone
- Itraconazole
- Iron
What are the names of the 4 H2-Receptor Antagonists (H2 Blockers)
- Cimetidine (Tagament)
- Ranitidine (Zantac)
- Famotidine (Pepcid)
- Nizatidine (Axid)
Pharmacokinetics of which agent?
- Rapidly absorbed from the intestine
- 1st pass hepatic metabolism
H2-Receptor Antagonists (H2 blockers)
Which 3 of the 4 H2 blockers have 1st pass hepatic metabolism?
- Cimetidine
- Ranitidine
- Famotidine
MOA of what agent?
- Exhibit competitive inhibition at the parietal cell H2 receptors
- Suppress basal and meal stimulated acid secretion
- HIGHLY selective and do not affect H1 or H3 receptors
H2 Receptor Antagonists (H2 blockers)
Which H2 blocker is most potent and which is least potent?
- Most potent: Famotidine
- Least potent: Cimetidine
H2 Receptor Antagonists (H2 blockers)
- Prescription doses maintain greater than 50% acid inhibition for how many hours?
- OTC doses have a duration of acid inhibition of less than how many hours?
- Rx: 10 hours
- OTC: <6 hours
Adverse effects of which agent?
–extremely safe drugs
–diarrhea, headache, fatigue, myalgias, constipation
H2 blockers
Adverse effects of which agents if given through IV?
–mental status changes
•confusion, hallucinations, agitation
H2 Receptor Antagonists (H2 blockers)
Adverse effects of which agent?
•inhibits binding of dihydrotestosterone to androgen receptors
–inhibits metabolism of estradiol, and increases serum prolactin levels
Cimetidine (H2 blocker)
Adverse effects of which agent?
–crosses the placenta
•administered to pregnant women only if absolutely necessary
–secreted into breast milk and may therefore affect nursing infants.
H2 blockers
Drug Interaction of which H2 blocker?
•Interferes (inhibitor) with several important hepatic cytochrome P450 drug metabolism pathways,
Cimetidine
Drug Interaction of which H2 blocker?
•binds 4–10 times less than cimetidine to cytochrome P450.
Ranitidine
