Test 2 - Diarrhea & Vomiting (Josh) Flashcards
Which receptors in GI tract regulate bowel motility?
Cholinergic Receptors
Opioid (Mu) Receptors
—— acts on cholinergic receptors in GI tract to ——-
Dicylomine
decrease bowel motility
—- acts on mu receptors in GI tract to ——-
Loperamide
decrease bowel motility
Which diarrhea med is structurally similar to an opioid?
loperamide
structurally similar to meperidine, except it doesn’t cross BBB (therefore, no pain relief, euphoria, or addiction)
—— is used only for diarrhea, so it ——
Diphenoxylate/atropine
slows bowel motility
(it’s an opioid)
diphenoxylate/atropine is an —– and is insoluble in —-, which means….
opioid
water
can’t be abused by parenteral routes (remember it’s an opioid, so abuse can be a concern)
Why is diphenoxylate combined w/ atropine?
the atropine keeps the diphenoxylate (an opioid) from being abused
you can only get them as a combo now
Why is there little concern for abuse w/ the opioid antidiarrheals?
- administered at low doses so dependence doesn’t occur
BUT, high doses can illicit morphine like effects
In patients with IBD, opioids can cause —–
megacolon
abnormal dilation of large intestine
When is an antidiarrheal not good for a patient experiencing diarrhea?
When the diarrhea is caused by an infection of a food intolerance, the antidiarrheal will not address the underly ing cause
Emesis is a reflex caused by activating the vomiting center in the —- —–
medulla oblongata
once activated, this signals the stomach, diaphragm, and abdominal muscles
What are direct-acting stimuli?
stimuli that directly act on the vomiting center in the medulla oblongata
Where do direct-acting stimuli to the vomiting center originate?
- Cerebral Cortex (anticipation of fear)
- Sensory Organs (upsetting sights, noxious odors, pain)
- Vestibular apparatus of inner ear
What are indirect-acting stimuli?
stimuli that indirectly act on the vomiting center in the medulla oblongata by first activating the chemoreceptor trigger zone (CTZ)
How is the Chemoreceptor Trigger Zone (CTZ) activated?
- signals from the stomach/small intestine traaval along vagal afferents
- direct action of emetogenic compounds (anti-cancer drugs, opioids, ipecac) that are carried to CTZ in the blood
MOA: ondansetron (anti-emetic drug)
blocks serotonin receptors (5-HT3)
clean drug b/c it only involves one receptor
Most popular anti-emetic drug?
ondansetron
Side effects of ondansetron (anti-emetic drug)
few side effects
- headache, diarrhea, dizziness
- constipation
can PROLONG QT INTERVAL!!! (only super-high doses)
promethazine is a —– antagonist to treat —–
dopamine
n/v
Is promethazine (anti-emetic) a clean drug?
No
blocks:
- dopamin-2
- histamine-1
- alpha-1
Which antiemetic is contraindicated in children under 2?
promethazine
Anti-emetic Drugs
- ondansetron
- promethazine
- prochlorperazine
- metoclopramide
MOA: prochlorperazine (anti-emetic)
acts on dopamine-2 receptors
notes:
- also a neuroleptic (for schizo)
- extrapyramidal side effects (acute dystonia, akathisia, parkinsonism)
Which anti-emetic drug has EPS side effects?
prochlorperazine
- acute dystonia
- akathasia
- parkinsonism
MOA: metoclopramide (antiemetic)
blocks dopamine receptors
What is a benefit of taking metoclopramide (anti-emetic)?
increases gastric motility
Which anti-emetic has a BBW that states you cannot take it for more than 12 weeks?
metoclopramide
Tardive Diskinesia is a serious side effect of ——
metoclopramide
What is the concern for IV administration of promethazine?
extravasation can cause gangrene and tissue necrosis
also, serious injury can occur w/ inadvertant perivascular or intra-arterial administration, or near a nerve
Which parenteral route is prefered for promethazine?
IM, due to extravasation of IV causing gangrene
Client teaching for promethazine IV?
report any burning or local pain
