GI: N/V/D/C Flashcards
vomiting: receptor involvement (4)
dopamine
cholinergic
histamine
serotonin
dopamine: vomiting
dopamine is found in GIT, the vomiting center of the brain, and the chemoreceptor trigger zone. lower medulla of brain.
cholinergic: vomiting
vomiting center
visceral afferents
histamine: vomiting
vomiting center
visceral afferents
serotonin: vomiting
vomiting center
assessing pt with vomiting
temporal relationship with meal or med? characteristics of vomit frequency past similar symptoms other symptoms lab values psych assessment
1st line tx: nausea
serotonin antagonists
phenothiazines
benzamides
2nd line tx: nauses
benzo corticosteroids antihistamines anticholinergics NK1 antagonists
phenothiazines drug examples (2)
prochlorperazine
promethazine
MoA phenothiazines
dopamine antagonist
indications for phenothiazines
chemo induced nausea/vomiting
motion sickness
post op
SEs phenothiazines
sedation dry mouth urinary retention blurred vision EPS
routes of phenothiazines
PO
paraenteral
rectal
benzamides: drug examples
metoclopramide
trimethobenzamide
MoA benzamides
inhibits dopamine receptors in GIT/CTZ
EPS may be seen in what drug groups?
phenothiazines
benzamides, less so
SE benzamides
sedation
EPS
serotonin antagonists drug suffix`
-setron
serotonin antagonist MoA
inhibits serotonin receptors in the vomiting center
uses of serotonin antagonists
severe chemo induced n/v
post op
YEs of serotonin antagonists
headache, malaise, constipation, hypotension, EPS, anorexia
issue with serotonin antagonists
QTc prolongation
watch electrolytes
dose limit for ondansetron re: QTc prolongation
16g single dose max
benzos: nausea
MoA
prevent limbic input from reaching the vomiting center
benzos: nausea
indication
lorazepam
anticipatory nausea
corticosteroids: nausea
dexamethasone for chemo induced n/v
Moa corticosteroids for nausea
unknown
antihistamines and anticholinergics for nausea
motion sickness
MoA of antihistamines/anticholinergics for nausea
inhibits cholinergic receptors which decrease stimulation of vomiting center
aprepitant (emend)
NK receptor antagonist
MoA aprepitant
quiets NK receptors found in GIT/CTZ are responsible for chemo induced N/V or post op
emend should be given with
corticosteroid
serotonin antagonist
combination therapy for nausea
using first line with one or two second lines, all with different MOAs. may decrease side effects bc you arent maxing out any of them
chemo induced nausea/vomiting
combo
ondansetron plus dexamethasone plus lorazepam
FYI for combination therapy for nausea
maintain hydration
mild N/V tx: (4)
benzos
antihistamines
anticholinergics
other remedies like coke syrup
moderate n/v tx: (4)
phenothiazines
dexamethasone
butyrophenones
benzamides
severe n/v tx:
metoclopramide
serotonin antagonists
aprepitant
combo regimens
diarrhea can be
acute
chronic
drug induced
acute diarrhea
lasts 72 hours after onset
chronic diarrhea
> 2 weeks
leading cause of diarrhea
viral gastroenteritis
if someone has chronic diarrhea, what is imprint to ask about
history of episodes
before treating diarrhea, consider
if it is wise to stop the diarrhea
non pharm diarrhea tx
stop solid foods for 24 h
avoid dairy
rehydrate
anti peristaltic agents for diarrhea:
loperamide
diphenoxylate/atropine
antisecretory agents for diarrhea:
bismuth
octreotide
adsorbent agents for diarrhea
polycarophil
kaolin pectin
attapulgite
MoA octreotide
blocks serotonin and other peptides, used in VIPomas
anti peristaltic agent MoA
slows GI motility
anti peristaltic agents should be used cautiously in
infectious diarrhea
fyi for anti peristaltics
may see some sedation
anti peristaltic agents in children
use cautiously
adsorbants MoA
adsorb water - absorbs water in the GI tract
issue with adsorbants like polycarbophil, attapulgite, kaopectate
may absorb other drugs
main use for bismuth
traveler’s diarrhea
properties of bismuth subsalicylate
antisecretory
antimicrobial
adsorbant
bismuth subsalicylate toxicity
broken down into salicylate, watch if patient is on AC or excessive ASA.
treating acute diarrhea without fever or other symptoms
fluids and lytes
loperamide or diphenoxylate
diet restrictions
treating acute diarrhea with fever or other symptoms
check feces for WBC/RBC/O&P
after checking stool for WBC/RBC/O&P in the patient with diarrhea and fever, what do you do if symptoms are neg? pos?
neg: symptomatic therapy
pos: appropriate abx and symptomatic therapy
treating chronic diarrhea:
identify possible cause
do appropriate diagnostics (cultures, sigmoidoscopy, biopsy)
if no diagnosis is made in chronic diarrhea…
rehydrate
loperamide
adjust diet
if diagnosis is made in chronic diarrhea:
treat cause
diarrhea is often
minor and self limiting
who do we worry about re: diarrhea?
children
AIDs patients
elderly
immusuppressed
goals of diarrhea tx:
prevent excessive water/lyte loss
relieve symptoms
treat curable causes and secondary disorders
when do you order a GI consult for the pt with diarrhea? (8)
children < 3 pregnant frail/elderly mod/severe volume depletion chronic heart/renal/liver disease AIDs high fever bloody/mucous stools
contipation “defined”
< 2 BMs a week
most common cause of constipation
low fiber and inactivity
non pharm mgmt of constipation
diet changes inc fiber correct underlying disease increase fluids exercise
pharmacologic mgmt of constipation
laxatives CAREFULLY
drugs for constipation 5
bulk forming laxatives surfactants saline agents hyper osmotic agents stimulants
bulk forming laxatives are preferred because
they are not systemically absorbed
DoA bulk forming laxative
1-3 days
MoA bulk forming
holds water into stool increasing bulk and then stimulating a BM
AE bulk forming lax
flatulence
bulk forming lax is not
for quick relief
surfactants DoA
1-3 days
MoA surfactant (colace)
facilitates mixture of fats and aqueous materials
surfactants should be used as a
preventative, eps in those who shouldn’t be straining
saline laxatives should be used for
occasional constipation or bowel prep
use saline lax cautiously in
HTN
sodium restricted diets
renal disease
osmotic agents
lactulose
sorbitol
glycerin
polyethylene glycol
osmotic MoA
metabolizes solutes in GI tract, moving water osmotically and facilitating propulsion and evacuation.
stimulants: bisacodyl cause
colonic contractions and thus evacuation
why is bisacodyl enteric coated
so that it does not dissolve until it reaches the colon
bisacodyl is not for
everyday use
DoA stimulants for constipation
6-12 hrs
stimulant: senna
similar to bisacodyl but gentler. also promotes fluid accumulation in colon.
institue bowel regimens for those who take
opioids
verapamil
