GI Pharmacology Flashcards
1
Q
Gastroprotectants (5)
A
- Antacids
- H2 Blockers
- Proton Pump Inhibitors
- Sucralfate
- Misoprostol
2
Q
Anti-emetics (3)
A
- Maropitant
- 5-HT3 antagonists
- Metoclopramide
3
Q
Prokinetics (3)
A
- Metoclopramide
- Cisapride
- Erythromycin
4
Q
Appetite Stimulants (4)
A
- Capromorelin
- Mirtazapine
- Cyproheptadine
- Dronabinol
5
Q
Antidiarrheals (4)
A
- Bismuth-subsalicylate
- Kaolin-pectin
- Opioids
- Anticholinergics
6
Q
Three Stimuli for Gastric Acid Secretion and where they come from
A
- Acetylcholine (from the vagus nerve)
- Gastrin (from G cells)
- Histamine (from ECL cells)
7
Q
Most important gastric acid mediator?
A
Gastrin
8
Q
parietal cells
A
those which secrete gastric acid into the lumen via proton pumps
8
Q
Diseases of Hyperacidity
A
- Mast Cell Tumors (release histamine)
- Gastrinomas (rare but release gastrin)
8
Q
Why should we be careful when we suppress gastric acid?
A
It is important for digestion and also acts as a physical barrier in the small intestines. Acidic environments are also required for some drug administration so must be careful thinking about interactions.
9
Q
Diseases of Damaged Mucosa
A
- Esophageal Diseases
- GI Ulcers
- Gastritis/Gastroenteritis
10
Q
Antacids
A
bases combined with Al, Ca, or Mg that directly neutralize gastric acid
11
Q
Examples of Antacids
A
TUMS, Maalox, Mylanta
12
Q
Side Effects of Antacid Use
A
overall safe, but way overused therefore poorly effective, and also may bind other drugs causing reduced absorption
13
Q
H2 Receptor Antagonists (Blockers)
A
blocks histamine stimulation of acid secretion; RAPID onset
14
Q
Most Potent H2 Blocker
A
Famotidine (Pepcid)
15
Q
Least Potent H2 Blocker
A
Cimetidine
16
Q
Side Effect of Cimetidine
A
also a P450 inhibitor, meaning possible drug interactions
17
Q
Side Effects of H2 Blocker Use in General
A
minimal adverse effects but tolerance can develop
18
Q
Proton Pump Inhibitors (PPI)
A
directly inhibits acid release from parietal cells; slower onset (3-4 days)
19
Q
Which is more effective - H2 blockers or PPIs?
A
PPIs
20
Q
Examples of PPIs
A
the -prazoles
21
Q
Side Effects of PPIs
A
in dogs = diarrhea
in humans = gastric hypertrophy
22
Q
Sucralfate MOA
A
aluminum-containing polysaccharide which coaters ulcer craters, inhibits pepsin, and increases mucosal PGE
23
Indications for Sucralfate Use
gastric or duodenal ulceration
reflux esophagitis
24
How should sucralfate be administered?
SLURRY, and apart from other drugs and food!
25
Side Effects of Sucralfate
potential for lots of drug interactions (including ciprofloxacin and doxycyline)
26
Misoprostol MOA
PGE1 analog which increases mucosal blood flow, increases bicarbonate and mucus secretion, and also increases mucosal turnover
27
Indications for Misoprostol Use
prevents NSAID-induced ulcers, and also use in response to NSAID overdose/toxicity
28
Can misoprostol be used for steroid induced ulcers?
no
29
Side Effects of Misoprostol
cramping and diarrhea, also abortion
30
Who should absolutely not handle misoprostol?
pregnant women
and everyone should just wear gloves!
31
Most effective veterinary emetic?
Maropitant (Cerenia)
32
Maropitant MOA
blocks substance P binding to NK-1 receptors in the emetic center, CRTZ, and gut
33
CRTZ
chemoreceptor trigger zone
34
Indica Maropitant Use
acute gastroenteritis
renal/hepatic diseases
chemotherapy
motion sickness/vestibular disease
35
Side Effects of Maropitant Use
possible pain on injection, maybe sedation; can also mask clinical signs
36
Routes of Administration of Maropitant
PO
SQ
IV
37
Maropitant Dose PO vs. IV in Dogs
PO dose will be 2x the IV dose
38
Maropitant Dose PO vs. IV in Cats
PO and IV dose is the same
39
Ondansetron
5HT3 antagonist (serotoninergic receptor) in the CRTZ and emetic centers
40
What serotonin receptor is present in the emetic center?
HT3 (and a little HT2)
41
Adverse Effects of Ondansetron in Animals?
none
42
Can ondansetron and maropitant be used together?
yes
43
Metoclopramide ANTIEMETIC MOA
5-HT3 and DA2 (dopamine) antagonists at the CRTZ
44
Is metoclopramide more effective than maropitant and ondansetron?
no, it usually isn't used for antiemetic purposes anyway
45
Side Effects of Metoclopramide Use
excitation, diarrhea, cramping
46
Dirty Drug
high rate of unintended effects
47
Cisapride MOA
5-HT4 agonist (serotoninergic receptor) that moves the gut along (prokinetic)
48
Indications for Cisapride Use in Dogs
prevent reflux by increasing lower esophageal sphincter tone
49
Indications for Cisapride Use in Cats
colonic dysmotility, megacolon
50
Indications for Cisapride Use in Horses
colic
51
Why is cisapride not readily available?
causes severe arrythmias in humans, but has NOT been seen in animals
therefore needs to be COMPOUNDED
52
Metoclopramide PROKINETIC MOA
5-HT4 agonist and dopamine antagonist and acts on the smooth muscle of the GI tract (mainly upper GI vs. colon)
53
Indications for Metoclopromide Use
functional ileus (postop, enteritis, pancreatitis, foreign bodies); sometimes esophageal disease but doesn't work as well as cisapride
54
What prokinetic can be administered as a CRI?
metoclopramide
55
Erythromycin Prokinetic MOA
macrolide antibiotic which can stimulate motilin receptors in the stomach and upper small intestine to enhance gastric emptying
56
Which does is higher for erythromycin - prokinetic or antibiotic?
antibiotic (like, way higher)
57
ghrelin
secreted in stomach during fasted states and stimulates hunger directly via hunger centers and indirectly via the vagus nerve; also stimulates growth hormone
58
Capromorelin MOA
ghrelin agonist
59
Side Effects of Ghrelin
weight gain, insulin resistance
60
Contraindications to Capromorelin Use?
Diabetic and prediabetic patients!
61
Brand Names for Capromorelin
Entyce and Elura
62
Side Effects of Capromorelin in Dogs
diarrhea and lethargy
63
Side Effects of Capromorelin in Cats
vomiting and hypersalivation
64
Difference between Entyce and Elura?
concentration - that way both solutions are the same dose by weight (0.1mg/kg)
65
Mirtazapine MOA
as an APPETITE STIMULANT inhibits 5-HT2 and 3 receptors at the CRTZ and orexigenic centers
mirtazapine also used as an antidepressant with complicated MOAs
65
Routes of Mirtazapine Administration
oral (human approved) and transdermal (vet approved)
66
Side Effects of Mirtazapine
mainly behavioral, including:
vocalization
agitation
vomiting
ataxia
67
Cyproheptadine
similar to mirtazapine (serotonin antagonism at orexigenic centers) but no longer commonly used since we have a veterinary approved alternative; same side effects (excitation/aggression)
68
Dronabinol
synthetic THC that acts via the CB1 receptor in orexigenic and emetic centers
extra-label use in animals for chronic illness and appetite stimulation, but a schedule II - III drug
69
Do we use antidiarrheals a lot in vet med?
nah, because we really wanna find the cause (but used commonly with chemo because we know that's the cause)
70
Can bismuth-subsalicylate be used in cats?
absolutely not, it's toxic! (the salicylate part)
71
Indications for Bismuth-subsalicylate
acute diarrhea in dogs
72
Side Effects of Bismuth-subsalicylate and Kaolon-Pectin
can interfere with drug absorption
73
Kaolin-Pectin
GI protectant and adsorbent effective in both dogs and cats
74
Examples of Opioids as Antidiarrheals
Imodium and Lomotil
75
Opioid ANTIDIARRHEAL MOA
increased segmental contractions to decrease downstream movement (more time for absorption)
76
Indications for Opioid Antidiarrheal Use
acute (<48 hours), non-infectious diarrheas, chemo-associated, or a rare primary motility disorder
77
Contraindications for Opioid Antidiarrheal Use
infectious diarrhea
obstruction
cats
dogs with MDR1 mutation
78
Side Effects of Opioids as Antidiarrheals
cramping and abdominal discomfort
79
Anticholinergics
muscarinic cholinergic antagonists which block Ach receptors on gut smooth muscle
80
Are anticholinergics used for diarrhea? Why or why not?
NO
it can mask progression of signs, mimic obstruction on AXR, and enhance endotoxin absorption
