Antiematics Flashcards
Definitions:
Postoperative nausea and vomiting (PONV)
Nausea and/or vomiting occurring within 24 h of surgery
Definitions:
Early PONV
Within 6 h of emergence of anesthesia
Definition:
Late PONV
Within 6-24 h of emergence from anesthesia
Definition
Post Discharge Nausea and vomiting
From 24 h post-discharge up to 72 h
Name some of the consequences of PONV
What are the receptors being blocked at the emesis centers?
- Cholinergic (muscarinic 1), histaminic, dopamine 2, serotonin 5HT3,
neurokinin type 1
What are the risk factors for PONV?
What are the 5 independent factors predictive of Post discharge Nausea and Vomiting (PDNV)
- Women
- Previous episodes of PONV
- Younger age (<50 yrs)
- Opioid use in the PACU
- Nausea in the PACU
Approach to PONV
make sure you are using drugs from different classes.
How can you prevent PONV?
- Minimize perioperative opioids, if possible, while controlling pain
- Increasing intraoperative and postoperative opioids associatedwith much higher risk for PONV ¤ Uncontrolled pain also increases PONV
- Consider non opioid analgesia (NSAIDS, acetaminophen, gabapentin, ketamine, peripheral blocks, epidurals)
- Minimize neostigmine?
- Conflicting data regarding increased risk for PONV
- Prolonged paralysis if not used
First line tx for pharmacologic prophylaxis
Serotonin - 3 antagonist
When is Serotnin - 3 antagonist most effective to give?
- Most effective when given at the end of surgery
- because of shorter half-life
- while the patients are waking up.
- Palensotron –> choice if worried about Qtc
Type of antiematic that is given before induction
Neurokinin 1 Receptor Antagonist
Aprepitant
Fosprepitant [IV version of Aprepitant]
When can Dexamethasone be given?
What are the SE of Dexamethasone?
What are the associated risk?
When do you avoid it?
most effective when given at time of induction due to slow onset of action of at least 3-4 hours
- avoid in uncontrolled infection and hyperglycemia
What is the black box warning of Droperidol?
When is it GIVEN?
- FDA black box warning for QTc prolongation has reduced use (torsades)
- Monitor EKG for 2-3 h after drug administration
- Akathisia
- Dystonia
GIVEN: Effective when given at end of surgery due to short plasma half-life of ~3h
Dopamine antagonist that can be an alternative to Droperidol
when can you give it?
Haloperidol
*same black box warning
- induction vs end of sx doesn’t matter
What dose of Metoclopramide is associated with increased risk for adverse effects?
is more better?
What are the SE?
What are the population that warrants precautions/ contraindication
why?
- Doses of >20 mg have antiemetic effects, but associated with increased risk for adverse effects
- more is not better
Adverse SE:
- Dyskinesia, extrapyramidal symptoms, diarrhea, hypotension,
tachycardia
- Precautions Bowel surgery
- Contraindication –> Bowel obstruction
Histamine 1 antagonist adverse effects?
Doses for antiematic Propofol
How long does anticholinergic: scopalamine
when do they recommend putting the patch?
- 72 hours
- Recommended ideally, to be applied evening before surgery or 2- 4 hours prior to the start of anesthesia
SE:
VISUAL DISTURBANCES, DRY MOUTH, CONFUSION
Combinations and mutimodal therapy for PONV
*the more drugs the better
* most reduction is on the first agent you add
Prevention of PONV
RISK table
be agressive with wired JAW
Reasonable choice for Prevention of PDNV
Reasonable first choices
- Dexamethasone
- Scopolamine
- Palonosetron
- Aprepitant
* long acting type of drugs
Treatment of PONV
if a drug has a shorter half- life it is okay to repeat it > 6 hours except steroid.
*** If you gave a drug IN THE OR and it has been < 6 hours and they are still having n/v USE something of a different class [i.e neurokinin 1 inhibitor]
**Consider Serotonin 3 antagonist as first line as long as there is not case of absurd Qtc / TORSADES
