GI Flashcards
Why are head trauma and burn trauma patients susceptible to stress ulcers?
Hypermetabolic – producing more acid
List three mechanisms by which NSAIDs cause ulcers
Decreased gastric mucus production, cause anticoagulation, lower stomach pH
How does H. pylori contribute to ulcer production?
Surrounded by shield of bicarb causing chronic low-grade inflammation and irritation in stomach lining
What is Zollinger-Ellison syndrome?
And acid producing pancreatic tumor that can contribute to ulcer development
List two mechanisms of ulcer treatment
Increased mucus production, decrease acid
List four mechanisms to treat GERD
Decrease acid, coat and protect esophagus, improve LES tone, lower abdominal pressure
List two chemicals that stimulate acid production by the parietal cell
Acetylcholine and histamine
What chemical stimulates mucus production?
Prostaglandins
Which patients typically develop stress ulcers?
Critically ill, mechanically ventilated, head trauma and burn trauma
Differentiate the action of histamine at H1 and H2 receptors
At H1 receptors, stimulates allergic reactions
At H2 receptors, histamine stimulates gastric acid production
List examples ofhistamine-2 receptor blockers
Famotidine, ranitidine (all end in “tidine”)
What drugs commonly interact with H2 receptor blockers?
Acid loving drugs like itraconazole, digoxin, iron
List three adverse affects of H2 receptor blockers
CNS alterations, confusion, thrombocytopenia
How are H2 receptor blockers eliminated and what determines dose adjustment?
Renally illuminated: dose adjustment required when CrCl is less than 50 mL/min
What is bacterial translocation?
When normal gut bacteria moves into pulmonary system (causing nosocomial pneumonia) due to increased pH (seen in ICU patients)
What is the most potent form of ulcer treatment?
Proton pump inhibitor
How do proton pump inhibitors work?
Permanent inhibition of acid secreting ATPase pump in parietal cell (Final common pathway inhibition)
How are PPI’s eliminated?
Hepatically – good for patients with renal insufficiency
When are prokinetic agents used?
Used as anti-emetics, in cases of GERD, and treatment of gastroparesis, and to facilitate feeding tube placement
What patients often have gastroparesis?
Diabetics with nephropathy
Where are NG tubes placed?
Post pyloric stomach – to prevent reflux
How does metoclopramide work?
Enhances upper G.I. response to acetylcholine causing increased G.I. motility and accelerated gastric emptying, also blocks dopamine receptors in chemo trigger zone
How does cisapride work?
Increases LES tone and G.I. motility and accelerates gastric emptying, enhances G.I. response to Ach at myenteric plexus (effects seen throughout entire G.I. tract)
Which prokinetic causes diarrhea especially often?
Cisapride
