GI Medications Flashcards
What is late PONV defined as?
6-24hr post emergence
What are patient risk factors for PONV?
female, non-smoker, hx of motion sickness, previous PONV
What are surgical risk factors for PONV?
Length of procedure, laparotomies, gynecologic surgery, laparoscopic, ENT, breast, and orthopedic surgeries.
What are anesthesia risk factors for PONV?
Inhaled agents, Nitrous Oxide, Neostigmine, Narcotics, Etomidate
Where is the vomiting center located?
Medulla Oblongata
What are the 4 areas involved with nausea and vomiting?
CTZ, Vestibular apparatus, thalamus/cerebral cortex (CNS), and GI tract
Which neurotransmitters work in the vestibular apparatus and what is the receptor?
Acetylcholine (M1 receptor), Histamine (H1 receptor)
Which neurotransmitters work in the CTZ and what is the receptor
Dopamine (D? receptors), Serotonin (5HT3), Substance P (NK), Acetylcholine (M1), Histamine (H1)
Which neurotransmitters work in the GI tract and what is the receptor
Acetylcholine (M1), Histamine (H1), Serotonin (5HT3), Substance P (NK), and mechanoreceptors
What ending do anticholinergics have and what is an example?
“ine”
ex: Scopolamine, Atropine
What ending do benzamides have and what is an example?
“ide”
Ex: Metaclopramide
What ending do benzodiazepines have and what is an example?
“azolam”
Ex midazolam
What ending do butrophenones have and what is an example?
“peridol”
Ex. Haloperidol, Droperidol
What ending do 5HT3 have and what is an example?
“tron”
Ex: Ondansetron
What ending do NK1 anatgonists have and what is an example?
“itant”
Ex. Aprepitant
What ending do phenothiazines have and what is an example?
“azine”
Ex: Promethazine
What is an example of a glucocorticoid?
Dexamethasone
What is an example of a Cannabinoid?
Dronabinol
What is the following for Scopolamine:
MOA:
Dose:
Uses:
Side Effect(s)
MOA: blocks transmission from the vestibular apparatus to the medulla
Dose: 5mcg/hr x 72 hrs (give 4 hrs before for best results)
Uses: motion sickness, middle ear surgery, N/V with PCA or morphine
Side effects: visual disturbances
What is the following for metoclopramide:
MOA:
Caution with:
MOA: stimulates the GI tract via cholinergic mechanism and anti-dopaminergic effect
Use with caution in pts with Parkinsons and restless leg
What is the MOA and use with Midazolam?
Decreases the synthesis and release of dopamine within the CTZ. Use at the end of case for nausea
What is the following for Droperidol:
Class name:
MOA:
Dose:
Cautions:
Class: Butyrophenomes
MOA: Competitive dopamine antagonist. Receptor is D2 and ligands are dopamine and GABA
Dose: 0.625-1.25mg
Cautions: Parkinsons, restless leg syndrome, black box for high dose d/t long QTc
What is the following for Dexamethasone:
Class name:
MOA:
Dose:
Cautions:
Class: Corticosteroid
Dose: 4mg
Cautions: obese, diabetes (hyperglycemia)
What is the dose, onset, and side effects of zofran?
dose: 4mg
onset: 30-60 min
s/e: headache, diarrhea, QTc prolongation
What is tropisetron used for?
To treat carcinoid syndrome
What is the dose for Granisetron?
0.1mg per 24 hrs
What is the name of the 5HT3 antagonist that has an active metabolite?
Dolasetron
Where is substance P produced?
CNS and gut
What is a side effect or NK Antagonists?
can inhibit steroidal contraceptives for about 7 days
What are NK Antagonists commonly used for?
Chemo induced NV
How do NK Antagonists work?
Competitive antagonist at the NK1 receptor and prevents substance P from binding
What is the following for Phenothiazines?
MOA:
Receptors:
Use:
Examples:
MOA: antagonizes H1 and M1 receptors
Receptors: histamine, acetylcholine
Use: vestibular apparatus
Ex: promethazine
What are examples of h1 receptor antagonists?
Benadryl, meclizine, phenergan
What is the following for benadryl?
Use:
Dose:
Onset:
Duration:
Use: prophylaxis and treatment of allergic reactions
Dose: 25-50mg IV
Onset: 3 min
Duration: 1-7 hrs
What is the MOA and use of Dramamine (dimenhydrinate)?
MOA: H1 and M1 antagonist
Use: motion sickness and sleep aid
What are the 4 H2 receptor antagonist drugs?
Cimetidine/Tagamet
Ranitidine/Zantac
Famotidine/Pepcid
Nizatidine/Axid
Are H2 receptor antagonists selective or nonselective?
Selective
What side effects are seen with H2 antagonist toxicity?
CNS: slurred speech, delirium, confusion in elderly
Liver toxicity
Which H2 antagonist is most likely to cause CNS side effects and liver toxicity?
Cimetidine
T or F: H2 receptor antagonist cross the placenta and are secreted into breastmilk
True
Is cimetidine a P450 inducer or inhibitor?
inhibitor
Name 6 drugs cimetidine has an interaction with. What does it cause?
Reduced blood flow and inhibits P450 system. Dilantin Propranolol metoprolol labetalol diazepam calcium channel blockers
What syndrome is Omeprazole good for?
Zollinger-Ellison Syndrome
What is the following for Reglan:
MOA:
Dose
Cautions:
MOA: Cholinergic stimulation and dopamine antagonism. Causes contraction of lower esophageal sphinctor and stomach (prevents reflux), increases gastric and small intestine mobility. Crosses BBB and can be used as an antiemetic.
Dose: 10-30mg IV over 3-5 min
Cautions: Parkinsons, RLS, patients on MAOI’s, tricyclic antidepressants, GI surgery
Which GI medication does not change gastric pH?
Reglan
What are s/e of Reglan?
Abdominal cramping if given too fast, Extrapyramidal symptoms (crosses BBB), Prolongs Succ (inhibits plasma cholinesterase)