GI Drugs - Kumar TS Flashcards
0
Q
Which appetite stimulant is used in cats and acts through GABA?
A
diazepam (valium)
1
Q
What neurotransmitter stimulates appetite? Which one inhibits appetite?
A
Stimulated by GABA
inhibited by serotonin
2
Q
Which appetite stimulant for cats is an antihistaminic and antiserotonin agent?
A
cyproheptadine
3
Q
What is the anti obesity drug used for dogs?
A
dirlotapide
4
Q
What animals are NOT able to vomit effectively?
A
horses, ruminants, rodents
5
Q
What are the the 4 afferent sources that can stimulate vomiting?
A
CTZ
vestibular
peripheral sensory receptors
higher CNS
6
Q
What are the 5 neurotransmitters involved in vomiting?
A
dopamine, histamine, serotonin, Ach, substance P
7
Q
What is the most important neurotransmitter for the CTZ to initiate vomiting?
A
dopamine
8
Q
What is the neurotransmitters used to cause vomiting in the vestibular system?
A
Histamine and muscarinic
9
Q
What is the primary neurotransmitter for peripheral sensory receptors?
A
acetylcholinne
10
Q
What are the transmtters used for higher CNS centres for vomiting?
A
cholinergic and histamine
11
Q
What pathway initiates emesis from increased intracranial pressure?
A
limbic pathway
12
Q
What is the primary neurotransmitter used in psychogenic vomiting?
A
acetylcholine
13
Q
Where are NK-1 receptors found?
A
emetic center and CTZ
14
Q
Which peripheral acting emetic should not be dosed twice in cats?
A
ipecac
15
Q
What are the 3 peripheral acting/reflex emetics?
A
salt water, hydrogen peroxide, ipecac
16
Q
What are the 2 centrally acting emetics?
A
apomorphine
xylazine
17
Q
Which centrally acting emetic is used in cats?
A
xylazine
18
Q
What is the MOA for apomorphine?
A
opiod - dopaminergic receptors in CTZ`
19
Q
How is apomorphine adminisstered?
A
subq or conjuctival
20
Q
What is the contraindication of apomorphine?
A
animals with existing central depression because it depresses respiratory centers
21
Q
What is the MOA of xylazine?
A
stimulates alpha 2 receptors in CTZ
22
Q
What are the side effects of xylazine?
A
bradycardia
23
Q
What can be used to prevent emesis at the vestibular apparatus?
A
anti histamines
24
What antimuscarinic can cross the BBB in dogs to prevent emesis?
scopolamine
25
What are the SE of antimuscarinics?
xerostomia, drowsiness, constipation, urine retention
26
What are the 5 anti emetic drugs acting on the CTZ?
1. phenothiazines
2. butyrophenone derivatives
3. metoclopramide
4. peripheral serotonin antagonists
5. Nk1 receptor blockers - cerenia
27
What antiemetic drugs are "broad" spectrum?
phenothiazines
28
What should be done before giving animals phenothiazines (ace)?
fluid replacement
29
What are the contraindications of phenothiazines?
animals with seizures
31
What anti emetic effectively antagonizes apomorphine induced emesis?
metoclopramide
32
What is the MOA for metoclopramide?
dopamine antagonist, serotonin agonist and serotonin receptor antagoonist to CTZ
33
What CTZ anti emetic blocks transmission to CTZ an interferes with action of serotonin on peripheral receptors in GI tract?
peripheral serotonin antagonists (cyproheptadine)
34
What drug acts by blocking NK-1 receptor?
maropitant citrate (cerenia)
35
Why can't cerenia be used in puppies less than 11 weeks of age?
can induce bone marrow hypocellularity
36
What are the 3 ways anticholinergic drugs exert its antiemetic activity?
inhibit vagus
relax GI smooth muscle
inhibit GI secretions
37
What receptors do butyrophenone derivatives act on?
antidopaminergic
38
What are the 2 SE of butyrophenone derivatives?
sedation and hypotension
39
What drug effectively antagonizes apomorphine induced emesis?
metoclopramide (reglan)
40
Why is the bioavailability of metclopramide only 50%?
extensive hepatic first pass metabolism
41
What are the SE of metclopramide in horses and cats?
hyperactivity, restlessness, tremors
42
What group of drugs are indicated for emesis induced by chemotherapeutic agents?
peripheral serotonin antagonists
43
What peripheral serotonin antagonist is used in small animals?
cyproheptadine (periactin)
44
What are some other examples of peripheral serotonin antagonists?
granisetron, palonosetron, ondansetron
45
What anti emetic is a NK-1 receptor blocker?
maropitant citrate (cerenia)
46
What is the contraindication of maropitant citrate (cerenia)?
puppies less than 11 weeks - bone marrow hypocellularity
47
What are the 3 ways anticholinergics exert antimetic activity?
inhibit vagus
relax GI spasm
inhibit GI secretions
48
What is the one drawback of anticholinergic drugs?
delays gastric emptying - dont use for more than 3 days
49
What are the 3 MOA for drugs to modulate gastric acid secretion?
block endogenous secretagogues
block proton pump
enhance cytoprotective effect
50
Which antisecretory drug is anticholinergic and selective for gastric M1 receptors?
pirenzepine
51
Which H2 receptor antagonist (of the antisecretory drugs) has the longest duration of action?
famotidine
52
What is the order of potency for H2 receptor antagonists of the antisecretory drugs?
famotidine>ranitidine>nizatidine>cimetidine
53
What drug is clinically useful in preventing acetaminophen toxicity in case of accidental overdose?
cimetidine
54
What are the SE of H2 receptor antagonists?
thrombocytopenia, rebound acid hypersecretion, relapse ulcers, cutaneous drug eruption in cats
55
What is the MOA of omeprazole (prilosec)?
inhibits proton pump
56
What are the clinical indications of omeprazole (prilosec)?
short term treatment of gastric ulcers associated with gastrinomas
57
What are the 4 adverse reactions to omeprazole (prilosec)?
1. suppression of acid barrier - bacteria
2. aspiration pneuomonia (megaesophagus)
3. hypergastrinemia
4. inhibits CYp450
58
What drug does not alter serum gastrin levels, hence prevents rebound acid hypersecretion?
misoprostol (cytotec)
59
What are the 3 non-systemic antacids?
salts of aluminum, magnesium, calcium
60
What is the antacid of choice for mild ruminal acidosis?
aluminum hydroxide
61
What drug is used as a systemic antacid?
sodium bicarbonate
62
What are the 4 SE of antacids and which drug is most associated with each SE?
constipation - Al and Ca
Diarrhea - Mg
Hypercalcemia - Ca
hypophosphatemia - Al
63
What drug is considered a potent agent in gastroduodenal ulcer healing caused by NSAIDs?
misoprostol
64
What drug binds to the gastric ulcer, protects it, and promotes healing?
sucralfate
65
What cytoprotective drug should be used cautiously in cats?
bismuth subsalicylate (glucoronidation)
66
What is the MOA of bethanechol?
cholinergic agonist, enhances amplitude of GI contractions
67
What are the indications of bethanechol?
postoperative ileus, urinary retention
68
What are the SE of bethanechol?
obstruction, peritonitis, intestinal wall is compromised
69
What is the MOA of metoclopramide?
enhances release of Ach in GI. peripherally antagonizes D2 receptors (blocks inhibitory)
70
What are the 4 actions of metoclopramide?
increase tone of esophageal sphincter
increase GI contractions
relax pyloric sphicter, rapid emptying
penetrates BBB - antagonizes D receptors
71
What are the 2 clinical indications of metoclopramide?
reflux esophagitis
| gastric motility disorders
72
What drug has the broadest spectrum of all the prokinetic agents?
cisapride
73
What are the indications for cisapride?
same as metoclopramide, constipation (mega colon in cats), and post operative ileus
74
What is a prokinetic agent that peripherally antagonizes dopamine receptors only?
domperidone
75
What are the main indications for using anticholinergic drugs for GI?
control diarrhea in calves and mild colin
76
What is the net effect of using opiods on the GI?
decreased GI motility and secretions
| increase tone of sphincters
77
Opiods are superior to antimuscarinics in treating what?
non specific diarrhea
78
What are the contraindications for using opiods during diarrhea?
when diarrhea is from invasive bacterial infection
79
What is diphenoxylate used for clinically?
anti-diarrheal
80
What is the active metabolite of diphenoxylate?
difenoxin
81
What does loperamide do?
reduce excessive intestinal secretion, prolongs transit time
82
What drug is a tincture of opium and used as an antidiarrheal in foals?
paregoric
83
What Gi protectant and adorbent should be used cautiously in cats?
bismuth subsalicylate
84
What 2 drugs absorb E-coli enterotoxins?
Bismuth salts and activated charcoal
85
What is the best choice for emergency treatment of poisoning?
activated charcoal
86
What should be done after administering activated charcoal?
saline laxative 30-45 minutes afterwards
87
What does cholestyramine bind to?
acidic side chains of bile acids
88
What is the clinical indication for cholestyramine
pruritis associated with increased bile acids
89
What are the adverse effects of cholestyramine?
nausea, constipation, steatorrhea, decreased B vitamins
90
What kind of stool do cathartics/purgatives produce?
more fluid than laxatives
91
What are the 3 emollient laxatives?
mineral oil, docusate sodium, paraffin
92
What are aspects of emollient laxatives?
unchanged, not absorbed, soften and lubricate fecal mass
93
What are aspects of bulk forming laxatives?
hydrophilic in nature, reflex peristaltic contractionn
94
What are the 2 bulk forming laxatives?
bran, psyllium granules
95
What is the most useful mild laxative for horses with sand colic?
psyllium granules
96
What animals are saline/osmotic purgatives contraindicated in?
dehydrated animals
97
Which osmotic purgative is fermented to organic acids and lowers the pH of colon contents?
lactulose
98
What can lactulose be used to treat?
dogs and cats - constipation, hepatic encephalopathy
horses - hepatic encephalopathy
can be admin by rectum
99
What are examples of irritant/stimulant cathartics?
castor oil, ricinoleate, anthraquinones
100
What is the MOA of irritant cathartics?
stimulate local myenteric reflexes, provoke fluid accumulation in intestinal lumen by active secretory mechanisms
101
What irritant stimulant can cause superpurgation in horses when administered repeatedly?
anthraquinone
102
What is the MOA of neuromusular purgatives?
muscarinic actions - increase motility
103
What is the contraindication of neuromuscular purgatives?
mechanical obstruction of intestine
104
What is the contraindication of ALL cathartics??
animal showing signs of abdominal pain
105
what are the adverse effects of overdosing cathartics?
diarrhea, abdominal colic, dehydration, shock
106
What type of enema preparations should not be used in cats?
ones that contain phosphate
107
What can be given to foals to help pass the meconium?
docusate sodium
108
What do cholagogues do?
contraction of gall bladder
109
What do choleretics do?
increase secretion of bile
110
What can be used to dissolve gallstones non surgicially?
Ursodeoxycholic acid (UDCA)
111
What drug can reduce the surface tension of gas bubbles causing them to coalesce?
dimethicone
112
What drug is used in the prevention and treatment of frothy bloat?
poloxalene
113
What is contra indicated in ruminal bloat and stabalizes foam?
fish oils
114
What do phenothiazines NOT control for emesis?
labyrinthine stimulation (vestibular?)
115
What are the 3 centrally acting emetics that are antidopaminergics?
phenothiazines
butyrophenones
metoclopramide
116
What are examples of phenothiazine drugs?
```
chlorpromazine
prochorperazine
triflupromazine
promethazine
trifluperazine
```
117
What are examples of peripherally acting antiemetics?
demulscents, antacids, protectants such as kaolin, pectin
| anticholinergic drugs, prokinetics
118
What can chronic administration of antisecretory drugs to GI result in?
achlorhydria (malabsorption)
119
What are the 2 SE associated with using misoprostol for decreasing gastric secretion?
diarrhea
| increases uterine contraction (pregnancy contraindicated)
120
How does omeprazole inhibit the proton pump?
goes to acidic environment of parietal cells, protonated and irreversibly binds pump
121
What 2 non systemic antacids can be combine to balance bowel movements?
aluminum and magnesium
122
What does sucralfate require in order to break up and bind to ulcers?
acidic environment
123
What part of Bismuth subsaliicylate is absorbed?
salicylate
124
What is postoperative illeus?
atony or paralysis of stomach or bowel
125
What is the most potent and broad spectrum prokinetic agent?
cisapride
126
What prokinetic acts PERIPHERALLY as a dopamine antagonist?
domperidone
127
Mineral oil should not be used with what because emulsification of the oil would facilitate its absorption?
docusate sodium
128
What species should diphenoxylate be used cautiously because it causes excitabilty?
cats
129
What happens to castor oil after it is ingested?
hydrolyzed by pancreatic lipase into glycerol and ricinoleic acid
130
What does ricinoleate do?
reduces absorption of fluid and stimulates peristalsis
131
What are 2 substances that are cholagogues?
dietary fat and concentrated magnesium sulfate
132
What can be administered for a retention enema thru a catheter?
acetylcysteine - breaks bonds
