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
What is one potential serious side effect of cisapride (Propulsid)? How is cisapride regulated as a result?
QT interval prolongation (torsades)
Propulsid limited access program w/ black box warning
What drugs can interact with prokinetic agents like cisapride and metoclopramide?
Acetylcholinergics
Why is Prilosec often preferred to antacids?
Antacids must be taken four times a day, have chalky consistency, only neutralize existing acid
What is the effect of aluminum and magnesium respectively?
Aluminum – constipation, magnesium – diarrhea
AcMd
Which patients must be careful when taking antacids?
Patients with hypertension – antacids can contain sodium
What is Misoprostol?
A prostaglandin analogue that increases mucus in the gut to prevent NSAID induced ulcers
List two brand names of Misoprostol
Cytotec, Arthrotec (diclofenac and Misoprostol combination)
Why does Misoprostol not increase pain if it is a prostaglandin analogue?
Affects a different family of prostaglandins
List two adverse affects of Misoprostol
Diarrhea and uterine contractions (avoid in pregnancy)
Which G.I. medication is a category X for pregnancy?
Misoprostol -abortifacient
What is polyethylene glycol used for?
Treatment for constipation (do not confuse with propyleneglycol or ethylene glycol)
List whether the following medications are stimulants or lubricants: Docusate sodium, bisacodyl, castor oil, senna
Docusate sodium – lubricant bisacodyl – stimulant
Castor Oil – lubricant
Senna- stimulant
What is simethicone and how does it work?
Surfactant that decreases formation of gas bubbles in G.I. tract to prevent flatulence
What is Lomotil?
An antimotility agent for treating diarrhea (contains an anti-spasmodic and an anti-cholinergic)
How does Loperamide (Imodium) work to treat diarrhea?
Decreases gastric motility
Which G.I. disturbing bacteria should never be treated with anti-motility agents?
C diff – toxin should be flushed out
What is first-line defense medication for ulcerative colitis?
Sulfasalazine (sulfapyridine and aspirin combination)
What treatment for ulcerative colitis has systemic effects?
Corticosteroids – should be used as last resort
What medication is best for irritable bowel syndrome?
Dicyclomine: anti-spasmodic/anti-cholinergic specific to intestinal musculature
List eight anti-emetics
Antihistamines, phenothiazines, 5-HT3 (serotonin) receptor blockers, prokinetics, BDZs, Canabanoids, corticosteroids, substance P receptor blockers
