GI Tract Flashcards
7 factors that decrease esophageal closure
Fats, chocolate, alcohol, peppermint, acidic beverages, red wine, carbonated drinks
4 H2 receptor blockers
Cimetidine, ranitidine, famotidine, nizatidine
Cimetidine
Inhibits p450
Anti-androgenic
What 3 H2 receptor blockers are metabolized in the liver
Cimetidine, ranitidine, famotidine
Side effects of H2 receptor blockers - 2
Bradycardia, confusion in elderly
Inhibitors of H+ formation
PRAZOLES
Omeprazole
Mechanism of inhibitors of H+ formation
Inhibits ATPase required to drive proton pump
What are inhibitors of H+ formation activated by
Prodrugs activated by acid
Are inhibitors of H+ formation acids or bases, strong or weak
Weak bases that stay in parietal cells
Side effects of inhibitors of H+ formation - 2
Hyperchlorhydria: lack of H+ production -> decreased Ca absorption -> osteoporosis
Decreased vitamin B12 absorption
Mechanism of antacids
Neutralize the acid
Systemic alkalinization
If cation is readily absorbed, then more anion can be absorbed
Order of cation absorbability
Na»Ca>Mg>Al
Na: form, speed, duration, neutralizing effect
NaHCO3, rapid, short, high
Ca: form, speed, duration, neutralizing effect
CaCO3, rapid, medium, high
Mg: form, speed, duration, neutralizing effect
Al(OH)3, slow, long, low
Al: form, speed, duration, neutralizing effect
Mg(OH)2, slow, medium, high
Sucralfate mechanism
Complex that when exposed to H+ becomes very viscous and binds to damaged mucosa
Not systemically absorbed
Sucralfate side effect
Excess Al absorption
What shouldn’t sucralfate be taken with and why
H+ depleters because it won’t be activated
Bismuth subsalicylate mechanism
Can increase mucous production in stomach and inhibit pylori growth
Bismuth subsalicylate side effects - 2
Darkening of feces with extended use
Unpleasant taste/odor in mouth
Misoprostol mechanism
Replaces PG-E lost after use of NSAIDs and GCs
Misoprostol side effect
Abortificient - increases uterine contractility
What combo of antibiotics are used for H pylori infections
Metronidazole, amoxicillin, clarithromycin, tetracycline
Metoclopramide mechanism
DA, 5HT antagonist that increase motility without increasing gastric secretion
Metoclopramide side effects - 3
Sedation, depression, Parkinsons-like symptoms
Erythromycin mechanism
Acts directly on motilin receptors
Erythromycin side effects - 4
Ototoxicity, pseudomembranous colitis, arrthymia, inhibits p450
Alvimopan mechanism
Blocks opiate receptor in gut
2 stool softener cathartics
Dioctal sodium sulfosuccinate and mineral oil
Dioctal sodium sulfosuccinate mechanism
Detergent that emulsifies colon contents
3 reasons we don’t use mineral oil
Won’t absorb fat-soluble vitamins
Aspiration pneumonia
Carcinogens
4 bulk-adding agent cathartics
Bran, methylcellulose, polybarbophil, psyllium
4 gastric irritant cathartics
Cascara, senna, castor oil, bisocodyl
Gastric irritant mechanism
Increases gastric motility and electrolyte secretion into gut
Gastric irritant side effects - 2
Nephritis and liver damage
3 osmotic agent cathartics
MgSO4, Mg(OH)2, polyethylene glycol
2 secretion enhancer cathartics
Lubiprostone, linaclotide
Lubiprostone mechanism
Acts on PG receptor to activate Cl channel in intestine - increases Cl and H20 secretion into gut
Linaclotide mechanism
Activates guanylate cyclase - increases Cl secretion into gut
Secretion enhancer side effect
Diarrhea
4 adverse effects of cathartics
Fluid imbalances - K loss
Mucosal injury
Malabsorption of nutrients
Suppress normal reflex function
4 antidiarrheal narcotic agents
Codeine, diphenoxylate, difenoxin, loperamide
Where does diphenoxylate primarily act and what drug is it given with
Acts primarily in gut and given with atropine to decrease abuse
Why doesn’t loperamide have opiate-like effect in CNS
Doesn’t cross BBB
Antidiarrheal absorbing agent
Bismuth subsalicylate
Bismuth subsalicylate mechanism
Binds bacterial toxins
3 antidiarrheal anticholinergic agents
Atropine, scopolamine, crofelemer
Why is there limited utility with anticholinergic agents
Multiple systemic side effects
Crofelemer mechanism
Blocks Cl channels in gut
2 miscellaneous antidiarrheals
Simethicone, alpha galactosidase
Simethicone mechanism
Changes gas surface tension of gas pockets
Alpha galactosidase mechansim
Increases metabolism of gas-producing oligosaccharides to digestible sugars
4 salicylates used for inflammatory bowel disorders
Sulfasalazine, mesalamine, olsalazine, balsalazide
SALAs
Salicylate mechanism
Decrease PG synthesis in gut
Salicylate composition and mode of entry
All have 5 amino salicylate
Oral - not sytemic
Salicylate side effect
Diarrhea
2 GCs used for inflammatory bowel disorders
Prednisone, budesonide
Infliximab use and mechanism
Used for inflammatory bowel disorders
Binds to TNF
Infliximab side effects - 2
Infections, response to Ab
2 other immunosuppressants used for inflammatory bowel disorders
Methotrexate, cyclosporine
Ipecac
Reflex stimulant to induce vomiting
Ipecac side effect
Cardiotoxic
2 central stimulants emetics
Apomorphine, digoxin
4 antihistamines anti emetics
diphenhydramine, dimenhydramine, meclizine, cyclizine
Anticholinergic anti emetic
Scopolamine patch
Scopolamine side effects - 3
Dry mouth, drowsiness, visual disturbances
2 THC derivative anti emetics
Dronabinol, nabilone
2 DA blocker anti emetics
Compazine, aphenothiazine
Compazine side effect
Extrapyramidal
5HT receptor blocker anti emetics
Ondansetron
SETRON Selective TeRminators Of Nausea
2 uses for SETRONs
Irritable bowel syndrome - treats diarrhea
Chemotherapy
SETRON side effect
Constipation