Antiemetics Flashcards
PONV defined as N/V within _______ hours of surgery
24`
Along with pain,____ is the highest complaint and leading cause of unanticipated hospital admission after outpatient surgery
PONV
__% of patients without prophylaxis have nausea who have general anesthesia
40
___% of high risk patients without prophylaxis experience PONMV
80
Risk Factors for PONV
patient factors: female, nonsmoker, hx PONV/motion sickness
surgical factors: long sx, certain procedures( GYN, laparoscopy, ENT, breast/plastics)
anesthetic factors: IA, N2O, neostigmine, opioids
Risk Factors for PONV in kids
weak association with age, greatest association is the surgical procedure :
- hernia,
- tonsils/adenoids/
- strabismus surgery,
- male genitalia
T or F: risk for PONV decreases with age
F - increases
PONV is associated with: (6)
- dehydration
- electrolyte abnormalities
- wound dehiscence, bleeding
- airway compromise
- unplanned admissions
- pt discomfort
Motion sickness is caused by stimulation of the
Vestibular apparatus
T or F: Opioids and morphine increase vestibular sensitivity to motion
T`
pt admionistered scopalamine may have visual disturbances due to
anisocoria (unequal pupil size)
indication scopalamine
- motion induced nausea and PONV
- trauma pt
Zofran acts on ___________ in GI tract and _________
Selective 5-HT3 receptor antagonist
Chemoreceptor Trigger Zone
S/E of Zofran
HA and diarrhea
cautious using zofran in what patients
prolonged QT interval: can lead to torsades
T or F: zofran safe in OB
F- questionable
Indications for Zofran
Preventative and rescue treatment for N/V,
used in chemo
Zofran
dose
DOA
metabolism
Dose: 4 mg IV
duration: 4-6 hours
extensive hepatic metabolism
Zofran (______)
Ondansetron
Decadron (________)
Dexamethasone
indicatios for decadron
Nausea and Vomiting prevention, ENT, traumatic intubations…..
MOA of decadron as antiemetic
Mechanism is unclear, proposed to centrally inhibit prostaglandin synthesis and control endorphin release
S/E of decadron
genital itching/burning (give after patient asleep), hyperglycemia
cautious using decadron in which patients
Careful in diabetics, wound healing issues
dose and DOA of decadron for N/V/ PONV
Dose: 4-12 mg IV on induction
duration: about 24 hours
Phenergan (________)
Promethazine
MOA of phenergan
- Phenothiazine,
- H1 receptor antagonist (antihistamine),
- Anticholinergic action (motion sickness),
- D2 antagonist in CTZ
why is phenergan considered a First-generation H1 receptor antagonist
due to sedation potential
phenergan indications
N/v anxiety
S/E of Phenergan
- Causes sedation
- potentiates sedative effects of benzos and opioids (Cesarean delivery)
- hypotension
- extrapyramidal symptoms (Akathisia)
phenergan
dose
onset
DOA
Dose: 12.5-25 mg IV (diluted and given slowly in good IV);
onset: 3-5 min
duration: 4-6 hours
Factors associated with pulmonary complications of aspiration: (2)
- Volume of gastric contents
- Acidity of the aspirated gastric contents
REGLAN (______)
METOCLOPRAMIDE
MOA of reglan and effetcs
MOA:
- Antiemetic action probably due antagonism dopamine-agonist effects in the chemoreceptor trigger zone
- Inhibition of dopamine receptors within the CNS….. Crosses the BBB
Effects:
- Gastrointestinal prokinetic,
- increases LES tone,
- enhances response to AcH in upper GI tract to enhance gastric motility and accelerate gastric emptying/reducing gastric volume
S/E of reglan
Can cause sedation, restlessness, extrapyramidal symptoms (tardive dyskinesia)
C/I of Reglan
Bowel obstructions and
Parkinson’s,
Restless leg syndrome, or
Movement disorders related to dopamine inhibition or depletion
indications for reglan
- Treatment of diabetic gastroparesis
- OB
- GERD
- Usually given in preop for aspiration prophylaxis
t or f: reglan alters gastric fluid pH
F – Does not alter gastric fluid pH
reglan:
dose
onset
DOA
Dose: 5-10 mg IV in preop
onset: 1-3 minutes, can be used as a rescue drug in PACU
duration: 1-2 hours
what adverse reaction can reglan cause
Potential for Neuroleptic Malignant Syndrome
Pepcid (_________)
Famotidine
MOA of pepcid
- H2 - receptor antagonist,
- inhibits gastric acid secretion/fluid volume and
- raises gastric pH
why is pepcid given in pre-op?
Given in preop to decrease risk of pulmonary aspiration in at risk patients
dose and onset of pepcid
Dose: 20 mg IV
Onset: 30 min – 1 hour
Vistaril (______)
Hydroxyzine
MOA of Hydroxyzine
Blocks Ach in the vestibular apparatus, blocks H1 receptors in the solitary tract, antihistamine
uses for vistaril
N/V, pruritus (pregnancy), antianxiety
S/E of vistaril
sedation, pain on injection
Vistaril
dose:
25 mg mixed with Ephedrine 25 mg IM 20 minutes before the end of surgery (careful in HTN patients/outpatients)
