Antiemetics - Ondansetron (Zofran) Flashcards
Where is the primary vomiting center located in the brain?
A) Cerebellum
B) Nucleus tractus solitarius (medulla)
C) Thalamus
D) Hypothalamus
B) Nucleus tractus solitarius (medulla)
Which of the following areas provide sensory input to the vomiting center? (Select 3)
A) Chemoreceptor trigger zone
B) Gastrointestinal (GI) tract
C) Vestibular system
D) Prefrontal cortex
A) Chemoreceptor trigger zone,
B) Gastrointestinal (GI) tract,
C) Vestibular system
What is the standard intravenous (IV) dose of Ondansetron for treating nausea and vomiting?
A) 2 mg IV
B) 4 mg IV
C) 8 mg IV
D) 16 mg IV
B) 4 mg IV
TxWes Reference
Dose: 4mg
Onset: 10 min
Duration: 4-9 hr
What is the oral dose range of Ondansetron for treating nausea and vomiting?
A) 2-4 mg PO
B) 4-8 mg PO
C) 8-16 mg PO
D) 16-24 mg PO
C) 8-16 mg PO
For treating pruritus resulting from neuraxial morphine, what is the recommended IV dose of Ondansetron?
A) 2 mg IV
B) 4 mg IV
C) 8 mg IV
D) 16 mg IV
C) 8 mg IV
What is the maximum dose of Ondansetron recommended for patients with liver disease?
A) 4 mg IV
B) 8 mg IV
C) 16 mg IV
D) 24 mg IV
B) 8 mg IV
What is the concentration of Ondansetron solution for intravenous administration?
A) 1 mg/mL
B) 2 mg/mL
C) 4 mg/mL
D) 8 mg/mL
B) 2 mg/mL
What is the primary mechanism of action of Ondansetron (Zofran)?
A) Dopamine receptor antagonist
B) 5-HT3 serotonin receptor antagonist
C) Histamine H1 receptor antagonist
D) GABA receptor agonist
B) 5-HT3 serotonin receptor antagonist
Ondansetron works by blocking serotonin receptors in which of the following locations? (Select 2)
A) Central chemoreceptor trigger zone (CTZ)
B) Peripheral gastrointestinal tract
C) Vestibular system
D) Central nervous system (CNS)
A) Central chemoreceptor trigger zone (CTZ)
B) Peripheral gastrointestinal tract
Which statement accurately describes Ondansetron’s central action?
A) Ondansetron acts centrally by blocking dopamine receptors in the brain.
B) Ondansetron acts centrally at the chemoreceptor trigger zone (CTZ) without causing significant neurological effects.
C) Ondansetron causes notable neurological side effects such as dizziness and confusion.
D) Ondansetron has central effects but primarily targets peripheral serotonin receptors.
B) Ondansetron acts centrally at the chemoreceptor trigger zone (CTZ) without causing significant neurological effects.
What is the primary ligand for Ondansetron (Zofran)?
A) Dopamine
B) Norepinephrine
C) Serotonin
D) Acetylcholine
C) Serotonin
Serotonin’s highest concentration in the body is found in which two primary locations?
A) Liver and Kidneys
B) Brain and Gastrointestinal tract
C) Lungs and Heart
D) Colon and Stomach
B) Brain and Gastrointestinal tract
Which type of nausea is Ondansetron (Zofran) not effective against?
A) Chemotherapy-induced nausea
B) Motion sickness / vestibular stimulation
C) Postoperative nausea
D) Nausea from radiation therapy
B) Motion sickness / vestibular stimulation
Which organs have detectable levels of serotonin, but are not the primary sites of its highest concentration? (Select 3)
A) Liver
B) Kidneys
C) Brain
D) Colon
A) Liver
B) Kidneys
D) Colon
What is the onset time for Ondansetron (Zofran)?
A) Delayed
B) Rapid
C) Slow
D) Variable
B) Rapid
Tx Wes Reference:
10 min
What is the approximate half-life of Ondansetron (Zofran)?
A) 1 hour
B) 2 hours
C) 4 hours
D) 8 hours
C) 4 hours
*Kane Preop Meds: give towards end of case bc don’t want PONV after when pt’s awake
Dose: 4-8 mg IV
*
What is the typical duration of action for Ondansetron (Zofran)?
A) 2-4 hours
B) 4-6 hours
C) 6-12 hours
D) 12-24 hours
C) 6-12 hours
TxWes Reference:
4-9hr
What is the primary metabolic pathway for Ondansetron (Zofran)?
A) Hydroxylation on the indole ring
B) Methylation of the nitrogen atom
C) Oxidation of the phenyl ring
D) Glucuronidation of the hydroxyl group
A) Hydroxylation on the indole ring
After hydroxylation on the indole ring, Ondansetron (Zofran) is further metabolized by which processes?
A) Hydrolysis and methylation
B) Conjugation with glucuronide or sulfate
C) Reduction and oxidation
D) Acetylation and phosphorylation
B) Conjugation with glucuronide or sulfate
Ondansetron (Zofran) may have reduced effectiveness in individuals with variations in which enzyme activity?
A) CYP3A4
B) CYP2D6
C) CYP2C19
D) CYP1A2
B) CYP2D6
Why should Ondansetron (Zofran) be used with caution in patients with congenital QT prolongation?
A) It may worsen renal function.
B) It can lead to a higher risk of torsades de pointes.
C) It may interact with other antihistamines.
D) It can cause severe gastrointestinal bleeding.
B) It can lead to a higher risk of torsades de pointes.
When should Ondansetron (Zofran) be administered in relation to emergence from anesthesia?
A) 5 minutes before emergence
B) 15 minutes before emergence
C) 30 minutes before emergence
D) 1 hour before emergence
C) 30 minutes before emergence
PONV Mordecai Fall 2024
Dolasetron (Anzemet)
Granisetron (Kytril)
Ondansetron (Zofran)
4mg within 15-20 of surgery end; data unclear on 4mg vs. 8mg
Palonosetron (Aloxi) Generally reserved for chemotherapy
Which of the following conditions require ECG monitoring when administering Ondansetron (Zofran)? (Select 4)
A) Hypokalemia (hypoK+)
B) Hypercalcemia
C) Hypomagnesemia (hypoMg2+)
D) Congestive heart failure (CHF)
E) Bradyarrhythmias
A) Hypokalemia (hypoK+)
C) Hypomagnesemia (hypoMg2+)
D) Congestive heart failure (CHF)
E) Bradyarrhythmias
or other QT interval prolonging meds
Which of the following side effects are commonly associated with Ondansetron (Zofran)? (Select 3)
A) Headache
B) Diarrhea
C) Rash
D) Prolonged QT interval
A) Headache
B) Diarrhea
D) Prolonged QT interval
