GI Meds + Intro to Vasopressors - Final Wrapup Flashcards
What are the Nausea & Vomiting Pathways?
Medulla
Chemoreceptor Trigger Zone
Vestibular Neural Pathway
Reflex & Midbrain Afferent Pathway
What is considered Early PONV?
2-6 Hrs
What is considered Late PONV?
6 - 24 Hrs
What is Considered Delayed PONV?
> 24 Hrs.
What is the population most at risk for PONV?
Non Smoking Female who is younger than 50 years old w/ a PONV hx.
How do risk factors relate to incidence of PONV?
Each risk factor = 20%
No risk factors = 10%
Which drugs can cause PONV?
Anesthetic Gas, N2O, and Opioids
What are the PONV risk factors for Kids?
> 3 years old
Strabismus Surgery
Surgery > 30 Min
Family Hx
What are some Anesthesia Considerations to reduce PONV?
Use Propofol
Regional Anesthesia
NSAIDs over Opiates
Should Neostigmine be reduced due to it’s PONV side effect?
No, Not Recommended
What do you do if PONV pretreatment does not work?
Try medication w/ different MOA
Which meds are recommended for Post Discharge N/V?
Dexamethasone
Scopolamine Patch
&
Rescue Meds
(Zofran, Phenergan)
Which meds are more effective when given BEFORE Induction?
Dexamethasone
Scopolamine Patch
Aprepitant
Amisulpride (Barhemsys)
Out of Zofran, Droperidol, and Dexamethasone, which drug is most effective for PONV?
All Equally Effective
Which drugs are classified as 5HT3 Antagonists?
5HT3 = Serotonin
Drugs that end in -setron
How are 5HT3 metabolized?
CYP450
What is the Half Life of Ondansetron?
4 Hrs
What is the Half Life of Granisetron?
9 - 11 Hrs
What is the Half Life of Dolasetron?
Prodrug
7 - 9 Hrs
What is the Half Life of Palonosetron?
40 Hrs
What are the Side Effects of 5HT3 Antagonists?
Generally Mild
QTc Prolongation
How might Dexamethasone work?
- Glutocorticoid Receptors in brain reduce emetic activity
- ↓Prostaglandin Synthesis to reduce GI contraction
- ↓Serotonin Activity
- ↓Anti-Inflammatory & Pain Effects
- ↑ Endorphins
- Augments other Antiemetics
What are the Side Effects of Dexamethasone?
- Low Risk for Single Dose
- Long Term use:
- Impaired wound healing
- ↑Glucose
- HTN
- AMS
Which D2 Antagonist is classified as Butyrophenone?
Droperidol
What effects does Droperidol have?
Anti-Emetic
Anti-Histamine
Anti-Serotonergic
Why is Droperidol normally given Post-Operatively vs Pre-Operatively?
Onset: 5-10 min
Peaks @ 1 Hr.
What are the Side Effects of D2 Blockers?
Dysphoria
Hypotension
Extrapyramidal Symptoms
Sedation
QT Prolongation
What is Droperidol’s Black Box Warning?
QT Prolongation & Sudden Cardiac Death
Rare
Must have ECG Monitoring for 3 hours
Which drugs are classified as D2 Phenothiazines?
Promethazine & Prochlorperazine
How do Phenothiazines compare to Butyrophenone D2 blockers?
More Highly Sedating & Highly Antihistaminergic
Also Available in Tabs, Gels, Suppository, Liquid
Which D2 Blocker was recently approved for only PONV?
Amisulpride (Barhemsys)
IV Only
How does Reglan work?
D2 Antagonist tht acts on CTZ for its Antiemetic Effects, mainly used for Gastric Emptying
- Increases Lower Esophageal Sphincter Tone
- Enhances Peristaltic Contractions & Gastric Emptying
- Does NOT alter Hydrogen Ion Secretion
How is Reglan Eliminated?
Liver & Kidneys
Crosses BBB & Placenta
Also Excreted in Breast Milk
What are Side Effects of Reglan?
Abdominal Cramps
Akathesia
What are some consideratios w/ using Reglan in terms of Drug Interactions?
Inhibits Plasma Cholinesterase
Increase CNS Depressant Effects
Increase EPS effects of other Drugs
Avoid w/ Hx of Seizure & Gastric Obstruciton
What drugs are H1 Antgonist?
Diphenhydramine (Benadryl)
Dimehydrinate (Dramamine)
Scopalamine
Which drug is a Neurokinin 1 Antagonist in the Brainstem & Vagal Complex?
Aprepitant (Emend) - PONV
Rolapitant - Chemo Induced NV
Netupitant - Chemo Induced NV
How is Aprepitant Elimintated?
Liver
Highly Protein Bound
Half Life: 9-13 hrs
What are the side effects of Aprepitant?
Neuropathy
Anemia
UTI
Neutropenia
How does Aprepitant effect Birth Control?
Reduce Effectiveness up to 4 Weeks
How can Aprepitant cause Bleeding?
Increases INR for 7-10 days w/ Warfarin
What is Dronabinol (Marinol) used for?
Chemo-Induced NV > PONV
No effect on Pain or Opiate Reduction
Which drugs are H2 Antagonists?
Cimetidine (Tagamet)
Ranitidine (Zantac)
Famotidine (Pepcid)
Nizatidine (Axid)
How do H2 Blockers work?
H2 Blockers competitively inhibits Histamine from binding to H2 receptor, preventing activation of adenylate cyclase
Only changes pH, not amt. of gut content
Which H2 Antagonists is the most potent? Which is the Least Potent?
Most Potent: Famotidine
Least Potent: Cimetidine (Shortest Acting)
How do H2 Blockers relate to Acid Pneumonitis?
May actually increase Pneumonitis
What are the Side Effects of H2 Blockers?
Thrombocytopenia
Diarrhea, Headache, Fatigue
Confusion
Dysrhythmias
What are Drug Interactions to consider when using Cimetidine or Ranitidine?
CYP-450 Inhibitor
Slows breakdown of Diazepam, Propanolol, Mepridine, Lidocain
What can happen w/ the pH increase from H2 Blockers?
Decreased Absorption of Ketoconazole, Iron, and Calcium Carbonate
What drugs are Proton Pump Inbibitors?
Drugs ending in -prazole
What are PPIs used for?
GERD
Hypersecretory Disorders
PUD
How do H2 Blockers compare to PPIs?
H2 Blockers work faster, but does not last as long as PPIs
What are the Side Effects of PPIs?
C Diff
Kidney Injury
Dementia
Reduced Absortion of Calcium, B12, Mag, and Iron
Which drugs reduce Surface Tension and allow water & lipids to penetrate stool?
Stool Softeners
Colace/Docusate
Ineffective on their own
Which Drugs Irritate the GI Tract and cause contractions and H2O influx?
Stimulant Laxatives
Senna
Dulcolax
Biscodyl
Cause Abdominal Cramps
Which drugs prevents H2O Reabsorption w/ oil barrier?
Rectal Lubricant
Mineral Oil
Risk of Aspiration
Which drugs draws water into GI tract to soften stool?
Osmotic Laxatives
Miralax
Mg++
Glycerin
Fleets
Lactulose (↓K & ↓NH3)
Which drug produces Chloride Rich Fluid Excretion?
Chloride Channel Activator
Lubiprostone (Amitiza)
1st dose may cause Syncope & Dyspnea
Which drugs Increase cGMP for GI Contraction & Speed Transit Time?
Guanylate Cyclase-C Activators
Linaclotide (Linzess)
Plecanatide (Trulance)
Black Box Warning - dehydration in kids
Which drugs Stimulate Colonic Peristalsis?
5HT4 Agonists
Prucalopride (Motegrity)
Tegaserod (Zelnorm)
Black Box Warning - suicidal ideation, CVA, TIA, MI
Which drugs block the effects of Opiates at the GI Tract?
Mu Antagonist
Naldemedine (Symproic)
Naloxegol (Movantik)
Methylnaltrexone (Relistor)
Only reduces GI effects, not pain
Which constipation drug Blocks Sodium/Hydrogen Exchange?
NHE3 Inhibitor
Tenapanor (Ibsrela)
Black Box Warning: Dehydration in Kids < 6 y.o
Which Diarrhea drug blocks Calcium for less GI Contraction?
Mu Agonists
Loperamide (Imodium)
Abuse/Misuse = Fatal Arrhythmias
Which Diarrhea medication reduces GI Motility and Blocks ACh Release?
Anticholinergics w/ Mu Agonist
Diphenoxylate/Atropine (Lomotil)
Which medication acts as a GI Protectant and Blocks Irritation?
Bismuth Subsalicylate (Pepto)
Black Stools might be mistaken for bleed
Which Diarrhea medication reduces water and stool more formed?
Psyllium (Metamucil)
Causes stomach pain & bloating
Which Diarrhea medication binds bile acids to reduce colon impaction?
Cholestyramin (Questran)
Can bind other meds, wait 1 hour after other meds or wait 4 hours before other meds if given before
What happens with Alpha-1 Receptor Stimulation?
Vasoconstriction
Bronchoconstriction
Smooth Muscle Contraction
GI Relaxation
What happens with Alpha-2 Receptor Stimulation?
Located in CNS
Reduce Sympathethic Outflow
Hypotension
Sedation
What happens w/ Beta-1 Receptor Stimulation?
Effects Heart
↑HR
↑Conduction Velocity
↑Inotropy
What happens w/ Beta-2 Receptor Stimulation?
Smooth Muscle Relaxation
Peripheral Vasodilation
Bronchodilation
↑Insulin Secretion
Hypotension
What happens w/ Dopamine 1 Receptor Stimulation?
Vasodilation
Diuresis
↑IOP
↓Gastric Secretion
Inhibit Aldosterone Release
What happens w/ Dopamine 2 Receptor Stimulation?
Vasodilation
Emesis
Prostaglandin Production
↑Gastric Secretion
Inhibit Aldosterone Secretion
Which receptors does Vasopressin work on?
Vasopressin Receptors: V1 & V2 Receptors
What happens w/ V2 Receptor Stimulation?
Water Reabsorption –> ↑Volume –> ↑BP
What happens w/ V1 Receptor Stimulation?
↑Baroreflex Sensitivity
Vascular Contraction
Starts SNS Activity
Stimulates RAS (Renin-Angiotensin System)
Which meds are Endogenous Catecholamines?
Epinephrine
Norepinephrine
Dopamine
Which receptors does Epinephrine work on?
Binds to Everything
- Low Dose: Beta-2
- Moderate Dose: Beta-1
- High Dose: Alpha-1
Which receptors does Norepinephrine work on?
Alpha-1
Alpha-2
Beta-1
(Inotropy > HR)
Which receptors does Dopamine work on?
Low Dose: D1 & D2
Moderate Dose: Beta-2 & Beta-1
High Dose: Alpha-1
Which receptors does Isoproterenol work on?
Beta-1
Beta-2
Most Arrhthmogenic
Which receptors does Dobutamine work on?
Very selective Beta-1
Which medications are Synthetic Catecholamines?
Isoproterenol & Dobutamine
Which drug is a Direct Acting Non-Catecholamine?
Phenylephrine
Which receptors does Phenylephrine work on?
Alpha-1
Alpha-2
Which medication is an Indirect Synthetic Non-Catecholamine?
Ephedrine
Promotes release of Norepinephrine
Alpha-2 Negative Feedback - Tachyphylaxis (Weaker effects)
Which receptors does Ephedrine work on?
Alpha, Beta, and Indirect Norepi Effects