Term
| An increase in parasympathetic activity ___ the GI sphincters while ___ motility and tone |
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Definition
Relaxes the sphincters
Increases motility and tone |
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Term
| The vagus releases ___, which stimulates ___ in the myenteric plexus. These neurons release ___, which stimulates ___, causing ___ |
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Definition
ACh--stimulates pre-junctional M2R
5HT--stimulates 5HT2 and 3-R, causing contraction of GI smooth muscle and antegrade movement |
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Term
| Sympathetic fibers release ___, which stimulates ___, located on ___. This causes ___, which ___. |
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Definition
NE--stimulates pre-junctional a2R located on parasympathetic fibers
Inhibits ACh release, which inhibits antegrade propulsion |
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Term
| Stimulation of smooth muscle MuR causes ___, but ___, so ___ stops. |
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Definition
Tonic contraction
But decreased motility and secretion
Antegrade movement stops |
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Term
| Stimulation of prejunctional parasympathetic fibers causes ___, which ___. |
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Definition
Partial inhibition of ACh release
Further suppression of antegrade movement |
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Term
| Intrinsic nerves: effects of 5HT (3) |
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Definition
5HT2R: contracts GI smooth muscle
Pre-junctional 5HT4R: amplifies ACh release
Antegrade movement (along with ACh) |
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Term
| Contraindications for emesis (4) |
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Definition
Petroleum stuff: can cause chemical pneumonia
Corrosives
CNS depressants
Stimulants: can ppt seizures |
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Term
|
Definition
| Stimulates CTZ => local irritation of the stomach and upper duodenum |
|
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Term
|
Definition
Diarrhea
Temporary drowsiness
Sedation
Lethargy
Fever
Diaphoresis
Chronic: emetine-induced cardiomyopathy |
|
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Term
|
Definition
Dexamethasone
Dimenhydrinate
Diphenhydramine
Dolasetron
Dronabinol
Hydroxyzine
Meclizine
Metoclopramide
Ondansetron
Promethazine
Scopolamine |
|
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Term
|
Definition
| M-R blocker in vestibular nuclei and reticular formation = antiACh |
|
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Term
|
Definition
Xerostomia
Sedation
Inability to concentrate
Amnesia
Fatigue |
|
|
Term
| Antihistamine/AntiACh antiemetics (5) |
|
Definition
Dimenhydrinate
Diphenhydramine
Hydroxyzine
Meclizine
Promethazine |
|
|
Term
| 5HT/DA-R blocker antiemetic |
|
Definition
Metoclopramide
-5HT3R: vagal afferent fibers and CTZ
-D2R: CTZ |
|
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Term
| 5HT3-R blocker antiemetics (2) |
|
Definition
Dolasetron
Ondansetron
5HT3R: vagal afferent fibers and/or CTZ |
|
|
Term
| Motion sickness prophylaxis (3) |
|
Definition
Dimenhydrinate
Meclizine
Scopalamine |
|
|
Term
| Motion sickness treatment (1) |
|
Definition
|
|
Term
| Pregnancy n/v prophylaxis (3) |
|
Definition
Dimenhydrinate
Meclizine
Ondansetron |
|
|
Term
|
Definition
|
|
Term
| Vestibular vertigo (Meniere's dz) n/v drugs (2) |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
Stimulates pre-junctional 5HT4R on cholinergic fibers
Enhances ACh release |
|
|
Term
| Metoclopramide: effects (3) |
|
Definition
Increased LES pressure
Gastric emptying
Antegrade movement of food through the GI tract |
|
|
Term
| Metoclopramide: indications (4) |
|
Definition
Clear stomach prior to GI endoscopy/surgery
Tx infantile esophageal reflux
Diabetic gastroparesis
Tx post-op vomiting |
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Term
| Bulk laxatives (3) and lactulose |
|
Definition
Calcium polycarbophil
Methylcellulose
Psyllium
Lactulose
Don't cause laxative dependence |
|
|
Term
| Methylcellulose: composition, MOA |
|
Definition
Indigestible bran, fruits, veggies
Attracts water => hydrogel with feces => increases bulk
Activates stretch receptors => increase peristalsis via local reflexes |
|
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Term
| Methylcellulose: effects (4) |
|
Definition
After 1-3 days
-Softens stool
-Increases volume and water content of feces
-Increases colonic transit rate
-Increases frequency of defecation |
|
|
Term
| Psyllium: composition, MOA |
|
Definition
Indigestible seed coat => hydrophilic mucilloid
Attracts water => hydrogel with feces => increases bulk |
|
|
Term
| Calcium polycarbophil: composition, MOA |
|
Definition
Hydrophilic resin
Draws water into bowel => increases bulk => activates local peristaltic reflexes |
|
|
Term
| Lactulose: composition, MOA, additional effect |
|
Definition
Disaccharide
Not absorbed => bowel bacteria degrade it into acids => osmotic effect = draw water into the colon => increases bulk => increased peristalsis via local reflexes
Acidification of the colonic lumen traps blood ammonia as ammonium |
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Term
|
Definition
Docusate
Doesn't cause laxative dependence |
|
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Term
|
Definition
| Anionic surfactant => lowers surface tension of feces => allows penetration of water => emulsification softens stool |
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Term
| Irritant colonic agent (1) |
|
Definition
Bisacodyl
Can cause laxative dependence |
|
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Term
|
Definition
| Irritation => increased accumulation of water and electrolytes => enhances peristalsis via local reflexes |
|
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Term
|
Definition
Soft, semifluid stool within 6-12 hrs p.o.
Purgative effect within 15-60 min per rectum |
|
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Term
| Osmotic purgative agents (2) |
|
Definition
Mg hydroxide
Polyethylene glycol
Can cause laxative dependence |
|
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Term
| Osmotic purgatives: MOA, effect |
|
Definition
Hypertonic => osmotic effect = draw water into the colon => increases peristalsis via local reflexes
Soft, semifluid stool within 6-12 hrs p.o. |
|
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Term
|
Definition
Bulk laxatives (methylcellulose, polycarbophil, psyllium) + lactulose
Stool softener (docusate) |
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Term
| Tx constipation indications (lots) |
|
Definition
Post op ab/anal/rectal surgery
Hemorrhoids, hernia, anal lesions, rectal prolapse
CAD, HTN, prior MI/CVA |
|
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Term
| Stool softeners are also added to ___ to prevent ___ |
|
Definition
Iron supplements
Prevent the constipating effect of iron |
|
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Term
|
Definition
Bisacodyl
Mg hydroxide
Polyethylene glyco |
|
|
Term
|
Definition
|
|
Term
|
Definition
Corticosteroids
Mesalamine
Olsalazine
Bulk laxatives: expand large bowel => prevent alternating segmental contractions => restore antegrade peristalsis
M-R blocker (dicyclomine): prevent bowel spasm |
|
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Term
|
Definition
Bismuth subsalicylate
Diphenoxylate
Loperamide
Octreotide
Polycarbophil |
|
|
Term
|
Definition
Diphenoxylate
Loperamide
Direct and indirect inhibition of GI motility despite increased tone => stasis allows absorption and consolidation |
|
|
Term
| Polycarbophil: indications |
|
Definition
Constipation: hydrates the feces
Diarrhea: consolidates |
|
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Term
|
Definition
|
|
Term
| Bismuth subsalicylate: S/E (3) |
|
Definition
Bismuth not absorbed, but 90% of the salicylate is => salicylate toxicity
Decreased absorption of tetracyclines
Turns stools gray-black and radioopaque (but not melena!) |
|
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Term
| Bismuth subsalicylate: antibacterial MOA, effect with other Ab |
|
Definition
Binds to SH groups of microbial proteins => destroy tertiary structure
Reduce their adherent properties => prevent binding to epithelium
Synergism! |
|
|
Term
|
Definition
| Stimulates somatostatin-R in the GI tract |
|
|
Term
| Octreotide: indications (2) |
|
Definition
Reduces diarrhea/flushing associated with carcinoid syndrome
Stop GI bleeding in patients with esophageal varices |
|
|
Term
| Tx bacterial diarrhea (1) |
|
Definition
Ab
Bismuth subsalicylate
No diphenoxylate/loperamide |
|
|
Term
|
Definition
Al hydroxide
Cimetidine
Esomeprazole
Famotidine
Mg hydroxide
Misoprostol
Omeprazole
Ranitidine
Sucralfate
Ab triple tx: clarithro, amox, omeprazole |
|
|
Term
|
Definition
Cimetidine
Famotidine
Ranitidine |
|
|
Term
| H2R blockers: physiologic effect |
|
Definition
Gastric pH rises to 3-4 (recurrence is common after stopping tx)
No effect on LES pressure, gastric motility/emptying, pancreatic/biliary secretion |
|
|
Term
|
Definition
Eradicate H. pylori
Neutralize gastric acids
Decrease secretion of gastric acids: H2R blockers, PPI, PGE analogs (misoprostol)
Construct protective barrier (sucralfate) |
|
|
Term
|
Definition
Weak bases slowly soluble in water => pH rises to 3-4
Al compounds: constipation
Mg compounds: diarrhea
Toxicity in patients with renal insufficiency |
|
|
Term
|
Definition
Inhibits P450
-Can't breakdown estrogen => anti-androgenic effects
-Increases the t1/2 of things like B-blockers, warfarin, diazepam
CNS effects: mental confusion to over psychosis in older patients/prior hx psych disease/large doses for long period |
|
|
Term
|
Definition
Esomeprazole (S-isomer)
Omeprazole |
|
|
Term
|
Definition
Inhibit gastric H-K ATPase
Blocks acid secretion 24-72 hrs |
|
|
Term
|
Definition
Inhibit basal, nocturnal, and stimulus-related acid secretion => pH rises to 4-5
Reactive increase in plasma gastrin concentration in some patients
No effect on LES pressure, gastric emptying/motility
No effect on release of IF from parietal cells (but increased pH partially inhibits absorption of protein-bound B12, but still no megaloblastic anemia)
No enterochromaffin hyperplasia/carcinoid tumors reported with long-term use |
|
|
Term
|
Definition
Stimulate PGE-R on gastric parietal cells => inhibit acid secretion (to simuli)
Protective effect on gastric mucosa
No effect on basal acid secretion |
|
|
Term
|
Definition
Diarrhea
Don't give to women of child-bearing potential without adequate contraception b/c it's an abortifacient |
|
|
Term
|
Definition
|
|
Term
|
Definition
Water-insoluble complex => polymerizes when pH <4 => sticky viscous gel that binds tightly to ulcerated gastric mucosa = protective layer
Poorly permeable to HCl, pepsin, trypsin, bile salts
Doesn't dissolve in the duodenum
Doesn't neutralize stomach acid or inhibit its secretion |
|
|
Term
|
Definition
Duodenal > gastric ulcers
Prevents relapse
Healing rate not affected by smoking
Don't give with anything that increases pH! |
|
|
Term
|
Definition
Aluminum toxicity in patients with renal failure
Hypophosphatemia in chronic alcoholism |
|
|
Term
| Stress ulcer prophylaxis (3) |
|
Definition
Antacids + H2 blockers: but predisposes to nosocomial pneumonia in ventilated patients due to the raised pH
Sucralfate: preferred for ventilated patients |
|
|
Term
| NSAID-induced gastropathy prophylaxis (2) |
|
Definition
Misoprostol: use only in high-risk patients (>60 yo, smokers, prior hx), prevents GI ulcer/bleed, no effect on the pharm of NSAIDs
Sucralfate: decreases heartburn and epigastric pain |
|
|
Term
| Corticosteroid-induced gastropathy prophylaxis (1) |
|
Definition
|
|
Term
|
Definition
PPIs
H2 blockers
Sucralfate
Antacids (symptomatic only) |
|
|
Term
|
Definition
| Capsule slowly releases 5ASA as it moves through the bowel |
|
|
Term
|
Definition
2 5ASA molecules joined together
Cleaved by bacterial enzymes in the large bowel |
|
|
Term
|
Definition
|
|
Term
|
Definition
Trace constituent of normal bile acid
Undergoes enterohepatic recirculation |
|
|
Term
|
Definition
Increase ratio of bile acids and phospholipids
-Inhibit HMG CoA reductase => decrease cholesterol synthesis
-Reduce GI absorption of cholesterol
-Decrease biliary secretion of cholesterol
Promote formation of liquid crystalline phase at the surface of gallstones => increases solubility of cholesterol |
|
|
Term
| Tx primary biliary cirrhosis (1) and MOA |
|
Definition
| Ursodiol: slows progression to required hepatic transplant |
|
|
Term
| Tx hyperlipoproteinemia (1) and MOA |
|
Definition
Psyllium: binds bile acids => depletes intrahepatic sterol pool => increased LDL-R, decreased LDL
Total decreased 5-15%
LDL decreased 10-20% |
|
|
Term
| Tx portal-systemic encephalopathy associated with chronic hepatic disease (1) and MOA |
|
Definition
Lactulose: acidification of colonic lumen traps ammonia as ammonium => decreased plasma NH3 by 25-50%, improves mental state and EEG in 75%
Good for acute and chronic tx |
|
|
Term
| Other things to know about portal-systemic encephalopathy associated with chronic hepatic disease tx (3) |
|
Definition
Lactulose as effective as neomycin, which decreases colonic ammonia by killing the bacteria
Co-tx with neomycin has additive effect
Don't use antacids since this opposes the acidification process |
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