Nausea/Vomiting Flashcards
Nausea
inclination to vomit or a feeling in the throat or epigastric region alerting an individual that vomiting is imminent
Vomiting
forceful expulsion of gastric contents due to retroperistalsis
Mose Common Causes of N & V
- infection (gastroenteritis)
- pregnancy
- medications
- motility disorders
Pathophysiology of Vomiting
- triggered by afferent impulses to cells in medulla from GI tract; impulses received by chemoreceptor trigger zone, cerebral cortex, vestibular apparatus
- cause efferent signals to go to GI and other tissues resulting in vomiting
Chemoreceptor Trigger Zone (CTZ)
- major area of chemosensory info
- stimulation of CTZ by chemicals usually results in vomiting
General Principles Important for Tx of N&V
- identify underlying cause
- usually self-limited
- maintain adequate hydration
Drug-Induced N&V
- common
- timing and reproducibility of NV in relationship to the administration of a drug
- discontinuing drug is the best therapy
Drugs that Commonly Cause N&V
- chemotherapy agents
- oral and some IV abx
- anticonvulsants (toxic levels)
- amphotericin (antifungal)
- narcotic analgesices
- theophyllien (toxic levels)
- digoxin (toxic levels)
Anticipatory N/V
- defined as N/V occurring before an expected event
- generally associated with the administration of chemo
- can result in sig. problems including delay of chemo administration
- commonly treated w/ benzodiazepines due to their amnestic properties
Refractory N/V
- defined as N/V despite the use of standard antiemetic therapy
- seen in up to 30% of chemo pts
- generally requires use of combination antiemetic regimens w/ more than one site or MOA
Anticholinergics MOA
-block muscarinic ACh receptors in vestibular system
Anticholinergics Generic
scopolamine
Scopolamine Trade Name
Transderm Scope
Anticholinergics Efficacy
- effective for preventing and treating motion sickness
- possibly post op NV
Anticholinergics AEs
- common: dry mouth and eyes, drowsiness, impaired eye accommodation
- rare: disorientation, memory disturbance, dizziness, hallucinations
Antihistamines MOA
-block H1 and muscarinic ACh receptors in vestibular system
Antihistamines Generics
- Dimenhydrinate
- Diphenhydramine
- Meclizine
Antihistamines Trade Names
- Dimenhydrinate
- Diphenhydramine
- Meclizine
- Dramamine
- Benadryl
- Antivert
Antihistamines Efficacy
- moderately effective
- more effective when combined w/ other antiemetics for chemo induced NV
Antihistamines AEs
- common: sedation, dry mouth, constipation
- less common: confusion, blurred vision, urinary retention
Phenothiazines MOA
-block dopamine stimulation of chemoreceptor trigger zone
Phenothiazines Generic
-Prochlorperazine
Prochlorperazine Trade Name
Compazine
Phenothiazines Efficacy
- effective for severe motion sickness
- vertigo
- NV with pregnancy
- chemo NV
- post op NV
Phenothiazines AEs
- sedation
- orthostasis
- EPS such as dystonia, tardive dyskinesia (abnormal lip/mouth movement), akathisia
Butyrophenones MOA
-block dopamine stimulation of chemoreceptor trigger zone
Butyrophenones Generics
- Droperidol
- Haloperidol
Butyrophenones Trade Names
- Droperidol
- Haloperidol
- Inapsine
2. Haldol
Butyrophenones Efficacy
- effective for preventing post op NV
- may be used for chemo NV for pts who can’t tolerate usual tx
Butyrophenones AEs
- sedation, agitation, restlessness
- droperidol may prolong QT interval
- EKG before and after dosing
- EPSE
Benzamides MOA
- block central and peripheral dopamine receptors
- increase GI motility (cholinergic effect)
Benzamides Generics (2)
- metoclopramide
- trimethobenzamide
Benzamides Trade Names
- Metoclopramide
- Trimethobenzamide
- Reglan
2. Tigan
Benzamides Efficacy
- used for post op NV, chemo NV, NV preg
- GERD, gastroparesis and migraine HA
Benzamides AEs
- common: sedation, restlessness, drowsiness, agitation, CNS depression
- less common: EPSE, HoTN, neuroleptic syndrome, SVT
Corticosteroids MOA
- through to be due to release of serotonin
- decrease BBB permeability
- decrease inflammation
Corticosteroids Generics (2)
- dexamethasone
- methylprednisolone
Corticosteroids Trade Names
- Dexamethasone
- Methylprednisolone
- Decadron
2. Medrol
Corticosteroids Efficacy
-used alone or in combo for post op, chemo, and radiation induced NV
Corticosteroids AEs
- common: GI upset, anxiety, insomnia
- less common: increase blood glucose, facial flushing, euphoria
Cannabinoids MOA
-work centrally but exact mechanism unknown
Cannabinoids Generics (2)
- dronabinol
- nabilone
Cannabinoids Trade Names
- Dronabinol
- Nabilone
- marinol
2. cesamet
Cannabinoids Efficacy
-used to prevent or treat refractory chemo NV
Cannabinoids AEs
-common: drowsiness, euphoria, abnormal thinking, dysphoria
Benzodiazepines MOA
-through to block input from cerebral cortex and limbic system from reaching vomiting center
Benzodiazepines Generics (2)
- lorazepam
- alprazolam
Benzodiazepines Trade Names
- Lorazepam
- Alprazolam
- ativan
2. xanax
Benzodiazepines Efficacy
-used to prevent and treat chemo NV
Benzodiazepines AEs
- common: sedation, amnesia
- less common: respiratory depression (caution in COPD), ataxia, blurred vision, hallucinations, paradoxical reactions
5HT3 Antagonists MOA
-selectively block 5HT3 receptors
5HT3 Antagonists Generic
ondansetron
Ondansetron Trade Name
Zofran
5HT3 Antagonists Efficacy
-very effective for prevention or tx of chemo or post op NV
5HT3 Antagonists AEs
- generally well-tolerated
- constipation, HA, somnolence, diarrhea
- all except palonsetron can prolong QT interval
NK1 Antagonist MOA
-block neurokinin1 receptors in CTZ and GI tract
NK1 Antagonist Generic
aprepitant
Aprepitant Trade Name
Emend
NK1 Antagonist Efficacy
- effective for preventing acute and delayed chemo NV in combo with 5HT3 antagonists and CS
- also effective for prevention of post op NV
NK1 Antagonist AEs
- common: fatigue, hiccups,
- less common: dizziness, HA, insomnia
- rare: transient increase in LFTs
2 Non-Pharm Options for NV Tx
- wrist bands with acupressure point 3 fingers below wrist fold
- ginger ale
Recommended Therapy for Motion Sickness
- dimenhydrinate/dramamine 50-100 mg q4-6 hr PRN
- scopolamine 0.5 mg q72 hr PRN
Recommended Therapy for Preg Induced NV
- pyridoxine (B6) +/- doxylamine (unisom); 10-25/12.5-20 mg 1-4x/day
- can also add promethazine, metoclopramide, trimethobenzamide, ondansetron
Recommended Therapy for Anticipatory NV
-lorazepam/ativan: 0.5 to 4 mg prior to chemo then q4-6 hr PRN
Recommended Therapy for Chemo Induced Highly Emetogenicity or Moderate AC
-5HT3 Antagonist + dexamethasone + aprepitant
Recommended Therapy for Chemo Induced Moderately Emetogenicity
-5HT3 Antagonist + dexamethasone
Recommended Therapy for Chemo Induced Low Emetogenicity
-dexamethasone 8 mg PO x1
Recommended Therapy for Post Op NV
- 5HT3 Antagonists (dolasetron, granisetron, ondansetron, tropisetron)
- dexamethasone
- droperidol
Recommended Therapy for Refractory NV
-add chlopromazine, prochlorperazine, promethazine, methylprednisolone, lorazepam, metoclopramide, dexamethazone if needed
