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67 Cards in this Set
- Front
- Back
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Where in the brain does acid secretion signal begin and how does it travel
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begins with a cephalic response, via vagus nerve
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What does the ECLs secrete and what does it support
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-histamine
-long term acid secretion |
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Gastrin is secreted by what and stimulates what
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-G cells in antrum of stomach
-parietal and ECL cells |
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How do prostaglandins promote stomach protection
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-activate Gi GPCRs
-decrease cAMP --> decreases acid -increase mucus and bicarbonate protection |
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Proton pump inhibitors:
-MOA -all require what -acid stabile/labil |
-covalently modify active site of H/K ATPase
-acid activation - prodrugs -acid labile |
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how are proton pump inhibitors dosed vs. how long are they active
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-dosed daily
-active for 2 hours, therapy relies on slow turnover of ATPase at the apical surface |
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what type of drug is the firstline treatment of hyperacidity and ulcers
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-proton pump inhibitors
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What 2 proton pump inhibitors can be given parenterally?
**ON EXAM** |
-pantoprazole
-lansoprazole |
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How can proton pump inhibitors can be given how?
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-gelatin capsules
-enteric coated tablets -mixed with bicarbonate |
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How much do proton pump inhibitors lower acid secretion by
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-90%
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6 uses of proton pump inhibitors
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-GERD, erosive esophagitis, peptic ulcers, zolinger-ellison syndrome, NSAID induced ulcers, part of H. pylori treatment
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T/F - all proton pumps are active all the time
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-false, only some are active
-so only those that are active are reacted with these drugs |
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how long does treatment with proton pump inhibitors take
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-2 to 5 days because not all proton pumps are active at any one time
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proton pump inhibitors are cleared where
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-thru the liver
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adverse reactions of proton pump inhibitors
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-if in hepatic failure clearance will be reduced
-nausea, pain, constipation, flatulence, diarrhea, -rare = myopathy, arthralgia, headaches, skin rashes |
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Which proton pump inhibitors interact with warfarin, diazepam and cyclosporine
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-esomeprazole, lansoprazole, omeprazole, rabeprazole
(ROLE) |
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What can occur with sudden withdrawl
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-hyper gastrinemia and gastritis
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How do H2 receptor antagonists work
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-block the base level of acid secretion maintained by ECL cells
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What are H2 receptor antagonists useful for
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-acid secretion at night and duodenal ulcers
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Which are more potent, proton pump inhibitors or H2 receptor antagonists
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-proton pump inhibitors
-H2 antagonists decrease acid secretion 70% for 24 hours with daily dosing |
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Cimetidine, ranitidine, famotidine, nizatidine are all what type of drug?
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-H2 receptor antagonists
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Adverse reactions of H2 receptor antagonists
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-diarrhea, headache, drowsiness, fatigue, muscle pain
-CNS effects in parenteral administration in the elderly |
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What does long term use of cimetidine at high doses cause
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-decreases testosterone binding to androgen receptor and hydroxlyation of estradiol causing galactorrhea in women and decreased sperm count, impotence and gynecomastia in men
-need a high dose (not seen w/OTC) |
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T/F - tolerance to H2 receptor antagonists develops quickly
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-true - w/in 3 days
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what problem is caused if you discontinue H2 receptor antagonists suddenly
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-rebound (esophagitis)
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What is sucralfate and how does it work
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-octasulfate of sucrose with aluminum
-forms sticky polymer coating that coverd epithelium -acid activated, avoid other GI drugs that lower acid -prefers to bind to ulcers over normal tissue |
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Sucralfate most common side effect
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-constipation
-will also block absorption of other drugs through the stomach |
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Antacids:
-MOA |
-neutralize pH of gastric contents
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Which is faster acting - Mg or Al
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-Mg is faster, Al is slower
(30 sec vs. 5 min) |
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T/F - using Mg is combination with Al is better than each alone
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true
-Mg stimulates emptying while Al delays emptying and slows motility |
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What is treatment of H. Pylori consist of
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-acid neutralization, cytoprotection and antibacterial agents
(proton pump inhibitor, antibiotics, bismuth) |
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Stimulation of enterochromaffin cells releases what?
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-serotonin
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Serotonin causes what to be activated
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-primary afferent neuron inside the gut
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How does GI motility happen
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local reflex pathways contract orally and relax anally
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T/F - activating muscarinic receptors activates coordinated motility so this is an approach
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-false - will not activate coordinated movement
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What are cholingergic derivatives used for (bethanechol)?
-MOA -side effects |
-help in urination post-surgery
-selectively activate M2 and M3 receptors -bradycardia, flushing, diarrhea, cramps, salivation, blurred vision |
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Neostigmine methylsulfate (acetylcholinesterase inhibitor) can be used to treat what GI ailment
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-ileus (bowel obstruction)
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Dopamine receptor antagonists:
-MOA |
-dopamine antagonizes Ach release so receptor antagonists enhance the normal ACh response
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metoclopramide -
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-a dopamine receptor antagonist
-used for N&V, laxative |
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tegaserod
-MOA -useage |
-partial serotonin 5-HT4 agonist
-improves lower bowel motility, used for IBS |
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Cisapride
-MOA -use |
-5-HT4 receptor and adenylate cyclase stimulant
-used for GERD |
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mycin antibiotics are all what?
-MOA -effect |
-motilin agonists
-peptide hormone that increases motility (secreted by ECF cells) -gastric dumping |
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Definition of consipation
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-<3 stools/week
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Osmotic laxatives:
-MOA -examples |
-cause water retention, may stimulate CCK receptors and increase motility
-cathartics - cause bowel emptying with watery stool -go-litely, milk of magnesia, magnesia products |
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lactulose, sorbitol, mannitol
-MOA -use |
-draw water into gut, drop pH by bacterial fermentation
-constipation with opioid use and vincristine |
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Docusate salts:
-MOA -category |
-surfactants that allow mixing of fatty substances and water in stool
-stool wetting agents (stool softeners) |
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T'/F - docusate saltes increase frequency of defacation
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-false
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bisacodyl
-moa -what would you warn patients of |
-irritant laxatives - make bowel release serotonin = more peristalsis
-not to chew tablets or mix with milk or antacids to ensure tablet reaches site of action in small intestine and avoid gastric irritation |
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castor oil
-MOA -uses |
-smooth muscle stimulant
-laxative, cathartic, induce labor -from castor bean - oil and rincin (poison) |
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glycerin
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-suppository that acts as a hydroscopic agent and lubricant
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bulk forming agents
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-based on colloids or polymers such as carboxymethylcellulose
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diphenoxylate diphenoxin piperidine derivatives, loperamide:
-MOA -potency -why they don't work as normal opioids |
-mu opioid receptor agonists that stop bowel mobility
-40-50x more potent than morphine -do not enter CNS |
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somatostatin/octreotide parenterals
-used for -side effect |
-combat diarrhea of hormone secreting tumors
-post-surgical dumping syndrome -diarrhea w/chemo -rest pancreas with pancreatitis -long term may cause gallstones |
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bismuth:
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-peptobismol = magnesium aluminum silicate and oil of wintergreen
-salicylate is released into the stomach and absorbed systemically |
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What can all play a role in emesis:
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-CNS, memory, environmental inputs, sensors of toxins, gut sensations, movement sensations
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What controls emesis centrally:
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the chemoreceptor trigger zone - at the bottom of the 4th ventricle
-transverses BBB so senses spinal fluid and blood for toxins -AND the solitary tract nucleus of the vagus nerve |
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What controls emesis peripherally:
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-senses
-inner ear -small intestine -pharynx (gaggin) |
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How do serotonin receptor antagonists help with nausea
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-act centrall at the CTZ and STN, peripherally at small intestine
-serotonin promotes gut motility, so antagonize it's receptor |
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ondansetron
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-a serotonin receptor antagonist used to help with emesis/nausea with chemo
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palonosetron
-delivery |
-5-HT2 antagonist
-highest affinity for receptor in its class -parenteral only |
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ondasetron, granistron, doasetron
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5-HT2 antagonists given in chemo for anti-emesis
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metoclopramide:
MOA Useage |
-dopamine receptor antagonist that strongly affects CTZ and increases forward motility
-preferred agent for chemo nausea |
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phenothiazines:
MOA -useage |
-primary targets D2 receptors in CTZ (dopamine receptor antagonist)
-motion sickness, NOT for chemo |
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major side effect of dopamine receptor antagonists
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-parkinsons-like symptoms
-will make parkinsons worse |
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antihistamines for anti-emesis:
-MOA -useage |
-H1 receptor antagonists, act primarily on brainstem and vestibular apparatus
-motion sickness and post-op emesis |
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cyclizine, promeethazine, hydroxyzine, diphenhydramine
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-antiemetic antihistamines
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cyclizine has what other effect than antiemesis
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-anticholinergic
-given to pts with abdominal cancer |
