Nausea and Vomiting Flashcards
Where is the chemoreceptor trigger zone located in the brain?
Area postrema, where the is no BBB
What kinds of drugs may stimulate the CTZ to cause vomiting?
Opiates
Emetigenic chemo drugs
Even uremia can do it
Where is the vomiting center of the brain located?
Medulla oblongata
What receptors are present in the vestibular system (whose activation may cause vomiting)?
Histamine (H1)
Acetylcholine
What receptors are present in the CTZ (whose activation may cause vomiting)?
Dopamine (D2)
5-HT3
NK1
List the two dopamine receptor antagonists used to palliate nausea/vomiting
Prochlorperazine
Metoclopramide
Prochlorperazine
MOA
Central dopamine receptor antagonist in the CTZ
Peripherally blocks vagus nerve
Prochlorperazine
Indications
Opioid related nausea and vomiting
GI disorders, inflammation, infection
Prochlorperazine
Adverse Effects
Extrapyramidal effects (Parkinson's-like effects) -AVOID use in Parkinson's patients
Dystonic reaction (kinked neck)
Metoclopramide
MOA
Dopamine receptor antagonist in the CTZ
Promotes motility in upper GI tract by blocking dopamine inhibition of cholinergic smooth muscle
Metoclopramide
Indications
Chemo-induced nausea and vomiting
Upper GI motility effects are good for Diabetic gastroparesis and Gastric stasis
Metoclopramide
Adverse Effects
Etrapyramidal effects
-Tardiev dyskinesia (uncomfortable movements, can’t stop)
Acute dystonic reactions
What is the serotonin receptor antagonist used to palliate nausea/vomiting?
Ondansetron
Ondansetron
MOA
Blocks 5-HT3 receptors in the CTZ and the GI tract
Ondansetron
Indication
Chemo-induced nausea
Radiation-induced nausea
Post-op nausea
Odansetron
Adverse Effects
QT prolongation (too much can lead to torsades)
Headache
Promethazine
MOA
Histamine (H1) receptor antagonist
Promethazine
Indications
Motion sickness treatment and prevention
Promethazine
Adverse Effect
Sedation
Scopolamine
MOA
Anticholinergic
Blocks Ach receptors in vestibular apparatus
Scopolamine
Indications
Treatment of motion sickness
Scopolamine
Adverse Effects
Confusion
Urinary retention
Acute narrow angle glaucoma
Dry mouth
Corticosteroids
Indications
Nausea due to increased intracranial pressure
Benzodiazepines (Lorazepam, Diazepam)
Indications
Anxiety-induced nausea/vomiting (often anticipatory)
What drug should be used in anxiety-induced nausea?
Benzodiazepines
Lorazepam
Diazepam
What drugs should be used in motion sickness?
Scopolamine
Promethazine
What drug should be used in nausea due to increased intracranial pressure?
Corticosteroids
