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Pharm 2 - GI 2

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isabellepjk's version from 2017-10-20 19:37

Cytoprotective agents

Question Answer
what are the 4 types/categories of drugs that are cytoprotective?Antacids, Prostaglandin E analog, Sucralfate, Bismuth subsalicylate
what do you use antacids for (in terms of being a cytoprotective agent)they are used to neutralize the excess acidity (they are weak bases)
what are the NON-systemic antacids?magnesium hydroxide, aluminium hydroxide, calcium carbonate (metal salts) (so. Chalk and MAAL hydroxide)
what should you know about aluminium hydroxide?causes constipation. ALSO binds up phosphate--> hypophosphatemia (aluminum buttplug will damage your electrolyte balance)
Inactivates pepsin, binds bile salts, induces local PG synthesis
Used for mild ruminal acidosis
what should you know about magnesium hydroxide?Increases gastric pH higher than Al(OH2)
laxative in nature (lubed up lax magnum)
which non-systemic antacid causes constipation? which one is a laxative? what else should you know about this?constipation= aluminum hydroxide. laxative= magnesium hydroxide. Can be combined to balance each other out.
hypophosphatemia caused by?aluminium hydroxide
what is the systemic antacid? what are side effects of being systemic?sodium bicarbonat. might cause metabolic alkalosis. Also, liberation of CO2 and distends the stomach--> bleching (or possibly bloating of rumen)
what is the Prostaglandin E1 analog acting as a cytoprotective agent? How is it protective(several ways)?misoprostol. Dec secretion of acid, AND improves mucus secretion AND improves bicarbonate secretion. ALSO improves blood flow and epithelial regeneration
Stabilizes mast cells and therefore, there will no ulcers
and working in healing gastroduodenal ulcers
misoprostol is a _________ drug, which means it has what affects?PGE1 ANALOGUE. So does stuff prostaglandins do. Which is dec secretion of acid (seen in other section), improve mucus secretion, inc bicarb secretion, inc blood flow and epithelial regeneration also
Sucralfate MOAat first it is a sulphated disaccharide (aluminium sucrose sulphate).
When the drug hits an ACIDIC enviro, sucrose released (from the aluminum hydroxide portion) and then cross polymerizes and binds to exposed anions of damaged GI epithelial cell membranes (polymerizes ulcerated area) and CREATES A PROTECTIVE LAYER!! (from acid, bile, and pepsin).
ALSO stim mucus and bicarb secretion. AND acts as a stimulus for the synthesis of local mediators PGs and sulfhydryl ions.
Binds epidermial growth factor on the ulcerated tissues
INC mucosal BF by inducing local nitric oxide and PG production
when should you not administer sucralfate?need ACIDIC pH to break apart and then bond to ulcerated areas and exert its effects, so DON'T GIVE WITH ANTACIDS or with ACID SECRETION SUPPRESSORS (H2 receptor antagonists or proton pump inhibitor)
It also decreases the oral bioavailability of concurrently administered drugs
Bismuth subsalicylate does what?ADSORBS E. COLI ENTEROTOXINS . Bismuth will produce antibacterial action and coat over the ulcerative tissue. The salicylate will then dec the gastric acid secretions (BIS will fight the Bacteria)
cautions about using bismuth subsalicylate?need to glucoronidate so cautions must be used in cats (cats dont like it when you coat them in pepto bismol)
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GI motility stimulators/ antagonists

Question Answer
what are the two groups of drugs which stim GI motility?(1) Cholinergic agonists (2) Prokineticagents
what are the two cholinergic agonists which stim GI motility?Bethanechol, carbachol (last call for the bathroom, comin' through) (oh yeah....and beth makes me wanna shit so bad id even do it in a car)
When should you never use a cholinergic agonist to stim GI motility?in MECHANICAL OBSTRUCTIONS (might lead to rupture of intestine)
what are the prokinetic agents?Metoclopramide, Cisapride, Domperidone
How does Bethanechol work?increases GIT and amplitude and contraction of sm mm in GIT
clinical indications? Contraindications of bethanechol?postop ileus and GI muscle atony
mechanical obstruction, peritonitis, if the intestinal wall is inviable.
what is the MOA of metoclopramide?inc ACH release from cholinergic neurons
sensitize sm mm to ach
blocks inhibitory effect of dopamine
has no action on gastric acid or pancreatic secretion
antagonizes emesis by INC tone of esoph sphincter and force and freq of castric contractions; promote gastric emptying.
Use in reflux esophagitis and gastric motility disorders
which prokinetic agent has the broadest spectrum? in what way?cisapride, because the effect is exerted on the whole GI tract (incld colon)
clinical uses of cisapride?bc of it's broad action, it not only is used as a prokinetic agent in general, but is also used to tx constipation with megacolon in cats;
post op ileus in equine
tx megacolon in catscisapride
MoA about cisapride?INC ach release and cholinergic Nt; 5HT4, mote potent than metoclop
MOA of domperidone?antagonize the dopamine receptor, but has prokinetic properities when acting peripherally
which two groups of drugs dec intestinal motility?anticholinergic drugs and opioid agonists
anticholinergics serve what kinda function in the intestines?antispasmodic and antidiarrheals
What are the anticholinergic drugs?atropine, scopolamine;
synthetics-aminopentamide, dicyclomine, glycopyrrolate, campylofine, propantheline
what are opioid agonists used for decreasing intestinal motility and secretions? (5)morphine, fentanyl, meperidine(in meperidine category, diphenoxylate, loperamide)
For non-specific acute and chronic diarrhea, which drugs are preferred?opioids
How do the anticholinergics work?Dec tone and propulsive GIT movements, dec intestinal secretions
What are the clnical indications of the anticholinergics?control diarrhea in calves and mild colic in horses
when are opioids contraindicated?in diarrhea due to infection (bc bacteria have more time to prolif bc inc intestinal transit time)
What is the intracellular MoA of opioids?INC K conductance and hyperpolarization; inhibits ach release in GIT
What are the opioid agonists?morphine, fentanyl, mereidine
How do the opioid agonists work?acts throgu mu receptors, decrease GI motility and gastric acid sectretions, increase tone of of the spinchter, so intestinal propulsive movement is reduced, thus more time for reabsorption of water can cause constipation
what is Difenoxin?active metabolite of diphenoxylate (which is a Meperidine congener, and meperidine is an opioid)
Loperamide is what?Meperidine congener (meperidine is an opioid) used to dec GI motility. SAFE FOR CATS
what is Paregoric, what is it used for?opioid which is used to dec GI motility--> preferred anti-diarrheal preparation in foals (foals love to eat pares! and they cure diarrhea!)
which opioid is safe for cats?loperamide (cats like to eat lop rabbits)
what are the side effects and contraindications of opiates, and why?increases tone of the sphincter, so intestinal propulsive movement is reduced , thus more time for re-absorption of water= constipation. This prolongs transit time. so DONT use in bacterial diarrheas, because gives bacteria more time to grow
what are the diarrheals she had listed as recommended for cats?Propantheline, Loperamide hydrochloride capsules, Bismuth subsalicylate suspension
How do meperidine congeners work?inhibit ach release form cholinergic neurons in the enteric myenteric plexus
Which meperidine congener can cause issues in cats and what are they?OD in cats causes excitablility, mydriasis, goose stepping giat, loss of balance
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NOTES

GI protectants and adsorbents

Question Answer
what are the 5 mian GI protectant/adsorbants?Bismuth subsalicylate, activated charcoal, cholestyramine, kaolin and pectin
which drug is used in treatment of emergency poisoning? what else should be done?activated charcoal (adsorbs many toxins and poisons). After charcoal is administered, wait a while, and then administer saline laxative to remove the charcoal-poison complex.
what should you know about the dosage of activated charcoal?10:1 charcoal:toxin dosing ratio
what is Cholestyramine? what is it used for?basic anion–exchange resin. usually used to bind to bile salts in the GI tract-- not able to be absorbed systemically, stays in GI. Can also be used to bind up other chemicals.
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