GI therapy Flashcards
1
Q
Drugs affecting appetite
A
-dirlotapide, anabolic steroids, benzodiazepines (valium, oxazepam), cyproheptadine,mirtazapine, megestrol acetate.
-also B vitamines and glucocorticoids (increase gluconeogenesis and antagonize insulin for hyperglycaemic effect)(steroid euphoria -increases appetite)
(catabolic efffect)
2
Q
Dirlotapide (Sientrol)
A
- microsomal triglyceride transfer protein (MTP) inhibitor developed to help dogs lose weight
- reduced fat absorption and satiety signal from lipid filled enterocytes and reduced appetite by increase peptide YY release into circulation
- not used in cats
3
Q
Anabolic steroids
A
- synthetic derivatives of testosterone that have enhanced anabolic effects with reduced androgenic effects
- antagonize catabolic effect of glucocorticoids and the negative nitrogen balance (need increase protein calories to improve N balance)
- stimulate hematopoiesis, appetite and weight gain.
- controlled, compounding pharmacy
4
Q
Benzodiazepines
A
- GABA induced effects and central inhibition of satiety centre in hypothalamus make it an effective appetite stimulant in cats.
- not effective appetite stimulants in dogs
- diazepam: IV, IM or oral. Cats will eat within a few sec of IV so have food ready
- Oxazepam: -less sedative then diazepam but also less effective at stimulating appetite
5
Q
Cyproheptadine (Periactin)
A
- antihistamine with serotonin antagonist action. also blocks Ca channels
- increase appetite by inhibiting serotonergic receptors that control satiety
- used in cats (may get CNS excitement and aggression and decrease seizure threshold)
6
Q
Mirtazapine (Remeron)
A
- antidepressant
- {NASSA) antagonist of presynaptic alpha 2 adrenergic receptors on NE and serotonin presynaptic neurons plus antagonist of post synaptic serotonin receptors (and H1).==>INCREASED NE and serotonin activity
- used for disease cans where appetite loss and nausea go together
- dogs and cats
7
Q
Megestrol acetate
A
- synthetic progestin
- significan anti-estrogen and glucocorticoid activity –> adrenal suppression.
- stimulates appetiite and promotes weight gain
- dont use in preg animals, uterine disease diabetes or mammary neoplasia
- toxicity in cats (adrenocortical suppression, adrenal atrophy, diabetes)
8
Q
Emetic drugs
A
- emergency situations following ingested toxin
- best act central at vomiting centre (directly or thro CRTZ)
- includes apomorphine, xylazine, hydrogen peroxide.
9
Q
Apomorphine
A
- most effective emetic drug
- opioid that acts as potent central dopamine agonist and directly stimulates CRTZ.
- more effective in dogs than cats
- oral or subq, or conjunctival or gingival membranes (not IM)
- can also get depressant effect on vomit centre, so if doesn’t work the first time then prob won’t work.
10
Q
Xylazine
A
Rompun
- alpha 2 adrenergic agonist
- reliable emetic, esp in cats
- stimulates the CRTZ
- can give sedation and hypotension too
- parenteral (IV or IM)
11
Q
Hydrogen peroxide
A
- stimulates vomiting when applied to back of mouth via the 9th cranial nerve.
- dont let it get aspirated-irritating to lungs
12
Q
Syrup of Ipecac
A
- emetine (toxic alkaloid) is active ingredient
- producing vomiting by being stomach irritant
- causes more problems then it helps. NOT RECOMMENDED!
13
Q
antiemetic drugs
A
- used to control vomiting
- continued vomiting leads to dehydration, acid-base imbalances and electrolyte disturbances and aspiration pneumonia
- metoclopramide, phenothiazine tranquilizers, anticholinergic drugs, serotonin antagonists, butorphanol, maropitant
14
Q
phenothiazine tranquilizers as anti emetic drugs
A
- alpha 2 adrenergic antagonists
- antagonize CNS stimulatory effects of dopamine
- decrease vomiting from a variety of causes, incl. motion sickness in the cat.
- also antihistaminic (dogs) and weak anticholinergic (cats) action
- includes chlorpromazine, prochlorperazine and acetylpromazine
15
Q
anticholinergic drugs as anti emetic drugs
A
- block cholinergic afferent pathways from the GI and the vestibular system to the vomiting centre
- less effective then other emetics alone
- more efficacious in motion sickness in cats than dogs(M1 muscarinic receptors found in the vestibular apparatus of the cat)
16
Q
Antihistaminic drugs as anti emetic drugs
A
- can block both cholinergic and histaminic nerve transmission responsible for transmission of the vestibular stimulus to the vomiting center in dogs (histamine not involved in cats)
- H1 blocking drugs used are diphenhydramine, dimenhydrinate, promethazine, cyclizine and meclizine.
- mild sedation
17
Q
Metoclopramide
A
Anti emetic!
Reglan
3 anti emetic mechanisms:
1. @low doses inhibits dopaminergic transmission in CNS (dopamine antagonist)
2. peripheral pro kinetic effect increasing gastric and upper duodenal emptying
3. @high doses, inhibits serotonin receptors (via antagonism) in the CRTZ
-less effective in cats than dogs!
18
Q
Serotonin antagonist as anti emetic drug
A
- serotonin antagonist for receptors located peripherally on vagal nerve terminals and centrally in the area postrema in the brain.
- not effective for motion sickness emesis
- good for emesis caused by cytotoxic drugs/radiation damage to GI mucosa–>serotonin release–>CRTZ.
- adverse cardiac effects
- include ondansetron, dolasetron and granisetron.
- good for radiation and chemotherapy patients
19
Q
butorphanol
A
Torbutrol
- effective antiemetic for dogs receiving chemo
- exerts antiemetic effects directly on vomiting center
20
Q
Maropitant
A
Cerenia
- NK1 receptor antagonist used to treat and prevent emesis in dogs
- safe and effective in cats
- blocks the binding of substance P in the emetic centre
- broad spectrum of action against various emetic stimuli (acute vomiting/low dose and motion sickness/high dose)
21
Q
Antacids
A
- most common are aluminum hydroxide, magnesium oxide/hydroxide or calcium carbonate
- neutralize stomach acid to form neutral salt and water
- not absorbed systemically
- also decrease pepsin activity, binding to bile acids in the stomach and stimulating local PGE1 production (cell turn over and healing)
- oxamin powder, MgOH boluses (carmilax), mild of magnesia (MgOH), Neigh-Lox
22
Q
H2 receptor antagonists used for gastric ulcers
A
-Cimetidine, ranitidine and famotidine
23
Q
Sucralfate
A
Sulcrate
- anti ulcer drug that has a cytoprotective effect on the GI mucosa
- disassociates in acid enviro of stomach to sucrose octasulfate (coats ulcer) and AlOH (neutralizes acid)
- not absorbed –>no side effects (exception in renal patients)
24
Q
Proton pump inhibitors
A
- Mostly benzimidazole derivatives
- irreversibly block the H+/K+ ATPase proton pump of the gastric parietal cell
- most effective at shutting down gastric acid production
- includes omeprazole
25
Q
Omeprazole
A
Gastroguard, ulcerguard
- proton pump inhibitor approved for use in horses
- human form Prilosec used in dogs
- inhibits H+/K+ proton pump at the luminal surface of the parietal cell that secretes hydrogen ions into the gastric lumen
- ulcers tend to come back after therapy
26
Q
Misoprostol
A
Cytotec
- synthetic prostaglandin E1 analogue that inhibits gastric acid secretion by direct action on the parietal cells (inhibits activation of histamine sensitive adenylate cyclase thus inhibiting GA secretion)
- mainly used as preventative
- during NSAID therapy for ex.
27
Q
Metoclopramide (motility)
A
-causes increase motility in upper GI by increasing sensitivity of Ach receptors and increasing amt of Ach release in upper GI and antagonizing dopamine (which inhibits GI motility)
-works from esophagus to small intestine
-readily crosses BBB- giving dopamine antagonism at CRTZ –> anti emetic
BUT get extrapyramidal signs too (bad)
28
Q
Domperidone
A
Motilium
- peripheral dopamine receptor antagonist (dopamine inhibits GI motility)
- esophageal, gastric and SI effects
- No CNS rxns! (effects of metoclopramide without
29
Q
Cisapride
A
Propulsid
- chemically related to metoclopramide (w/o crossing BBB or having anti dope effects)
- it enhances the release of Ach from postganglionic nerve endings of myenteric plexus and antagonized inhibitory actions of serotonin on myenteric plexus —->increased GI motility and increase HR
- most pro kinetic and broader activity than metoclopramide (does colon motility too)
30
Q
Prucalopride
A
Resotran
- potent partial benzamide agonist at 5-HT4 receptors
- increases colonic motility
- and gastric, pyloric and duodenal motility
- increased freq of defecation in dogs and cats (not diarrhea)
31
Q
Motilin receptor agonists
A
- macrolide antibiotics are motilin receptor agonists (incl. erythromycin and clarithromycin)
- also stimulate cholinergic and noncholinergic neural pathways to stimulate motility
32
Q
Acetylcholinesterase inhbitors for motility
A
- acetylcholinesterase inhbition causes prokinetic action (mostly proximal GI tract)
- Ranitidine and nizatidine are two H2 receptor antagonists that inhibit gastric secretion (via H2 antagonism) but are prokinetic due to Achesterase inhibition.
33
Q
Lidocaine (in motility)
A
- suppression of inhibitory GI reflexes by reduction of postoperative peritoneal irritation is mech of action
- also suppresses primary afferent neurons from firing and anti-inflam properties and direct stimulatory effects on sm. muscle.
34
Q
Alpha 2 adrenergic receptor antagonists (motility)
A
- role in regulating gastric tone and Ach release through presynaptic mech in enteric NS.
- adrenergic antagonists prevent the effects of NE on intrinsic neurons and stimulate sm. muscle
- treatment for ileus
35
Q
Castor oil
A
- stimulant (irritant) laxative
- potent stimulator of bowel.
- hydrolysed to ricinoleic acid in bowel —> increase h20 secretion in SI
36
Q
Raw Linseed oil
A
- stimulant (irritant) laxative
- similar action to castor oil –> increase h20 secretion in SI
- feed daily in horses to supply FAs and mild laxative effect
37
Q
Senna
A
- stimulant (irritant) laxative
- increases gastric fluid secretion and bowel motility—> laxative action
- Secokot and Exlax (OTC)
38
Q
Bisacodyl (Dulcolax)
A
- stimulates enteric nerves to cause colonic mass mvmts.
- also increases fluid and NaCl secretion
39
Q
Hyperosmotic cathartics
A
- laxative
- draw fluid into the bowel by osmosis–>increased fluid content of feces –>intestinal distension –> promotes peristalsis.
- ex. Mg salts (epsom salts, milk of magnesia, citro-mag), Na bisphosphate/phosphate (fleet enema)(Don’t use in cats), lactulose (Lactulax), polyethylene glycol
40
Q
Lactulose (Lactulax)
A
- hyperosmotic cathartic laxative
- organic acids produced from lactulose fermentation stimulate colonic fluid secretion and propulsive motility.
- can alter bowel flora = farts and bloating
41
Q
Polyethylene glycol
A
- hyperosmotic cathartic
- large MW, water soluble polymer used as bulking and softening agent from tx of constipation
- not metabolized and minimally absorbed in the intestines
- forms Hbonds with water–>high osmotic pressure in bowel lumen–>prevents absorption of h20 out of lumen (powder or soln form0
42
Q
Hydrophilic colloids
A
- “bulk laxatives”
- composed of non absorbed PSC cellulose derivatives
- drugs absorb h20 and increase mass of non digestible material in the bowel
ex. methylcellulose, pysillium (metamucil), prunes, wheat bran and canned pumpkin. - FIBER
43
Q
Lubricant laxatives
A
- act by coating the surface of the stool with h20 immiscible film and increase h20 content of feces
- also lubricant action
- usually contain mineral oil or white petroleum
- min oil in horses and cattle, Kat-Lax in cats (hairball passage)
44
Q
Stool softeners (surfactants)
A
- decrease surface tension and allow h20 to accumulate in the feces
- occasionally in horses (nasogastric tube)
- ex. dioctyl sodium, sulfosuccinate (DSS), dioctyl calcium sulfosuccinate(surfak, doxidan)
45
Q
Kaolin-Pectin formulations
A
-acts as a demulcent (substance forming soothing, protective film over mm) and adsorbent in tx of diarrhea.
-action like bacterial toxins binding to GI
(not Kaopectate anymore which now = bismuth subsalicylate)
46
Q
Activated Charcoal
A
- derived from wood, peat, coconut or pecan shells
- very effective for adsorbing bacterial enterotoxins that cause some types of diarrhea. Also adsorb many drugs and toxins and prevent GI absorption
47
Q
Bismuth Subsalicylate
A
PeptoBismol, Kaopectate, Corrective Mixture
- tx of choice for acute diarrhea (proven efficacy)
- Bismuth part may adsorb bacterial enterotoxins and produce gastric/intestinal protective effect
- Salicylate part is anti inflammatory action
- get black feces
- can get toxicity, esp in cats
48
Q
Anticholingeric drugs for anti diarrhea
A
- they signif decrease intestinal motility and secretions
- decrease segmental and propulsive intestinal sm muscle contractions
- decrease urgency with diarrhea in small animals, decrease fluid secreted in bowel and decrease abdominal cramps seen with hyper motility.
- can only be used in hyper motile forms of diarrhea tho or could make worse (stove pipe effect)(limited use in vet med)
49
Q
Atropine
A
- anticholergic drug
- not usually used for tx diarrhea because of systemic effects
50
Q
hyoscine butylbromide (buscopan)
A
- antispasmodic and anticholingeric drug that relaxes the smooth muscle of GI tract
- tx of uncomplicated colic
- decreases gut sounds
- beneficial in choke cases
51
Q
Opioids for diarrhea tx
A
- can have anti-secretory and anti-motility actions ( mu and delta receptors of the GI tract)
- decrease propulsive intestinal contractions and increase segmentation–> constipating effect
- increase tone if GI sphincters
- opiates also stimulate absorption of fluid, electrolytes and glucose (inhibition of Ca influx and decrease calmodulin activity)
- mostly used in dogs (less cats)
- dont use in infectious diarrhea (may increase absorption of bacterial toxins when slow GI transit time)
52
Q
Diphenoxylate (Lomotil)
A
- synthetic opiate that has specific action on GI tract (no system effects)
- used to tx diarrhea
- used in small animals and large neonates
- controlled substance
53
Q
Loperamide
A
Imodium (OTC)
- synthetic opiate with specific action on the GI tract (no systemic effects)
- used for diarrhea tx in small animals and neonate large animals
- dont use in “ivermectin sensitive” breeds (ABCB1 gene deletion dogs)
54
Q
Paregoric
A
- tincture of opium found in many antidiarrheal products
- controlled substance (corresponds to morphine)
55
Q
NSAIDS for diarrhea tx
A
- may be beneficial for diarrhea tx, and very impt in tx of septicaemia/ endotoxemia
- action may be anti inflam effect
- Anti-PG drugs may directly inhibit fluid and electrolyte hypersecretion by intestinal cells (increased cAMP)
- meloxicam calve diarrhea over a week old
- ketoprofen reduces fecal output in enterotoxigenic E. coli diarrhea
- use with caution
56
Q
Anti-endotoxin serum
A
- tx of equine and canine endotoxemia
- diarrhea tx?
- available for parvovirus enteritis in horses and clostridial diseases in ruminants
57
Q
Sulfasalazine (salasopyrin, Alzulfidine)
A
- 5-aminosalicylic acid product
- treatment of chronic colitis
- salicylic acid component is active in the GI- causes anti inflammatory effect
- anti-lipoxygenase activity, decreased IL-1, decreased PG synthesis and oxygen radical scavenging activity.
- commonly used in SAs for ulcer therapy or idiopathic colitis or plasmacytic/lymphocytic colitis after dietary causes ruled out
58
Q
Tylosin (Tylan)
A
- antimicrobial used for colitis
- often given on chronic basis as alternative to sulfasalazine therapy
- may have activity against mycoplasma, spirochetes and chlamydia
- powdered form for swine given in food
59
Q
Metronidazole (Flagyl)
A
- fair efficacy against Giardia
- given to dogs, cats and horses with IBD
- also good some other diarrhea cases due to activity against anaerobes prob.
- may be immunosuppressive on GI mucosa too
- has neuro effects tho
- ANTIDOTE = diazepam
60
Q
Glucocorticoids for chronic colitis
A
- tx colitis because anti inflam and immunosuppressive effects (colitis due to autoantibodies and T-cells directed against colonic epithelial cells or colitis due to lymphocytic/plasmacytic colitis)
- dogs, cats and horses
- prednisone or oral dexamethasone
- budesonide (Entocort-crohns disease)-dogs with IBD possibly. (HPA suppression tho)
61
Q
N-3 Fatty acids for colitis
A
- addn of N 3 FA to the diet makes fewer n-6 FA available for AA cascade (reduce inflame?)
- derm caps for SA and raw linseed for horses
62
Q
Azathioprine (Imuran)
A
- immunosuppressive drug used for colitis
- metabolized to 6-mercaptopurine which causes immunosuppression by interfering with nucleic acid synthesis and impairing lymphocyte proliferation
- monitor cats closely for SEs
63
Q
Ursodiol (Actigall)
A
- for hepatitis therapy
- naturally occurring hydrophilic bile acid that displaces the more hydrophobic bile acid pool in cholestatic liver disease
- suppresses hepatic synthesis and secretion of CHO and decreases intestinal absorption of CHO (allows solubilization of CHO containing gallstones)
- also increases bile flow and reduces hepatotoxic effect of bile salts by decreasing their detergent action
- uses: tx of CHO containing gallstones, idiopathic hepatic lipidosis and chronic active hepatitis.
64
Q
S-adenosylmethionine (SAMe) (Denosyl SD4)
A
- used for hepatitis therapy
- increases levels of hepatic glutathione which is a potent antioxidant that protects hepatic cells from toxins and death.
- used in compromised patients to maintain and protect liver fxn
- also used in other cdns of tissue oxidant injury and of RBC fragility caused by toxins or drugs (ones related to low glutathione levels)
65
Q
Colchicine
A
- used in hepatitis therapy (chronic with fibrosis, biliary cirrhosis)
- anti-fibroic properties (inhibits microtubular mediated transcellular mvmt of pro collagen into the ECM) and increases collegenase activity (increasing collagen degradation)
- anti inflam activity too
66
Q
Penicillamine
A
- hepatitis therapy
- frequent copper chelator used in dogs
- vomiting SE
67
Q
Trientine
A
- hepatitis therapy
- copper chelating agent
- less adverse effects than penicillamine
68
Q
Prednisone (hepatitis therapy)
A
-anti inflammatory effects beneficial in tx of chronic hepatitis in Bedlington terriers and west highland white terriers
69
Q
Zinc (hepatitis tx)
A
- essential cofactor for reducing hepatic copper []s
- Zinc leads to intestinal metallothionein (MT) production –> MT induction prevents serosal transfer of copper into blood
- zinc good follow up therapy after chelator therapy
- zinc shows reduced hepatic copper []s, decrease hepatic enz activity and improved hepatic histologic features after long term therapy
- SEs : nausea, vomiting and anorexia
70
Q
Antioxidants (Hepatitis tx)
A
- free radicals may play a role in initiating and perpetuating damage to liver in chronic active hepatitis
- therapy with vit E reduces oxidant damage to hepatic tissue
- NOT VIT C
71
Q
Milk thistle (Marin)
A
-natural remedy for hepatitis therapy
used for diseases of the liver and biliary tract
-Silymarin is active extract and contain flavonignans (antioxidants) which scavenge free radicals and inhibit lipid per oxidation (APPARENTLY)
