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{{Infobox drug reference
{{Infobox drug reference
| trade_names =  
| trade_names = Zofran
| drug_class =  
| drug_class = Anti-emetic
| drug_class_color =  
| drug_class_color =  
| uses =  
| uses = Prevention and treatment of chemo-induced, radiation induced nausea and vomiting, prevention of postoperative nausea and vomiting
| contraindications =  
| contraindications = Prolonged QT intervals, patients taking apomorphine
| routes =  
| routes = PO, IM, IV
| dosage =  
| dosage =  
| dosage_calculation = ondansetron
| dosage_calculation = ondansetron
| mechanism = 5HT3 antagonist
| adverse_effects = cardiac arrhythmias, cardiac arrest, constipation, headaches
| duration =
| metabolism = Liver oxidation followed by glucuronidation and sulfate conjugation
| halflife_elimination = 4 hours
}}
}}


Provide a brief summary of this drug here.
Ondansetron is a 5HT<sub>3</sub> receptor antagonist that is commonly used for the treatment and prophylaxis of chemo induced nausea and vomiting, radiation induced nausea and vomiting, and postoperative nausea and vomiting.  


== Uses<!-- Describe uses of the drug. If appropriate, add subsections for each indication. --> ==
== Uses<!-- Describe uses of the drug. If appropriate, add subsections for each indication. --> ==
* treatment and prevention of chemo-induced nausea and vomiting
* treatment and prevention of radiation induced nausea and vomiting
* Prevention of postoperative nausea and vomiting
* off-label use for the prevention of nausea and vomiting associated with pregnancy<ref name=":0">{{Citation|last=Griddine|first=Alexandria|title=Ondansetron|date=2022|url=http://www.ncbi.nlm.nih.gov/books/NBK499839/|work=StatPearls|place=Treasure Island (FL)|publisher=StatPearls Publishing|pmid=29763014|access-date=2023-01-05|last2=Bush|first2=Jeffrey S.}}</ref>


== Contraindications<!-- List contraindications and precautions for use of the drug. --> ==
== Contraindications<!-- List contraindications and precautions for use of the drug. --> ==


=== Absolute contraindications<!-- List absolute contraindications for use of the drug. If none, this section may be removed. --> ===
=== Absolute contraindications<!-- List absolute contraindications for use of the drug. If none, this section may be removed. --> ===
* Prolonged QT intervals
* Patients taking apomorphine <ref name=":0" /> as it can cause hypotension and loss of consciousness


=== Precautions<!-- List precautions for use of the drug. If none, this section may be removed. --> ===
=== Precautions<!-- List precautions for use of the drug. If none, this section may be removed. --> ===
* Maximum dose of 16 mg IV due to risk of QT prolongation and arrhythmias
* Maximum dose decreased to 8 mg IV or 8 mg PO in severe hepatic impairment
* Dissolving tablets formulations contain phenylalanine which can lead to irreversible neurological damage in phenylketonuria (PKU)<ref name=":0" />


== Pharmacology ==
== Pharmacology ==


=== Pharmacodynamics<!-- Describe the effects of the drug on the body. If appropriate, add subsections by organ system --> ===
=== Pharmacodynamics<!-- Describe the effects of the drug on the body. If appropriate, add subsections by organ system --> ===
* Metabolized by CYP2D6, CYP3A4, CYP2E1, CYP1A2 initially with oxidation followed by glucuronide and sulfate conjugations <ref name=":0" />
** Many polymorphisms with four different phenotypes
*** Poor metabolizer (no functional allele)
*** Intermediate metabolizer (less activity than one functional allele)
*** Extensive metabolizer (two functional allele, most common phenotype)
*** Ultrarapid metabolizer (three functional allele)


==== Mechanism of action<!-- Describe the mechanism of action for the primary uses of the drug. --> ====
==== Mechanism of action<!-- Describe the mechanism of action for the primary uses of the drug. --> ====
* Antagonism of the 5HT<sub>3</sub> receptors
* Centrally, ondansetron antagonizes the 5HT<sub>3</sub> receptors in the area postrema <ref name=":0" />
* Peripherally, ondansetron antagonizes the 5HT<sub>3</sub> receptors on the vagus nerve within the GI tracts which forms synapses within the nucleus tracts solitarius (a region also responsible for vomiting)
** Predominant mechanism for its anti-emetic effect


==== Adverse effects<!-- Describe any potential adverse effects of the drug. --> ====
==== Adverse effects<!-- Describe any potential adverse effects of the drug. --> ====
* Cardiac arrhythmia
* Cardiac arrest
* Constipation
* Headache
* dry mouth
* malaise
* drowsiness
* sedation
* pruritus
* transient elevation in liver function test


=== Pharmacokinetics<!-- Describe the pharmacokinetics of the drug. --> ===
=== Pharmacokinetics<!-- Describe the pharmacokinetics of the drug. --> ===
* Peak plasma concentration about 1.5 hours after an 8 mg PO dose
* Plasma half life is approximately 4 hours<ref name=":1">{{Citation|last=Zabirowicz|first=Eric S.|title=Pharmacology of Postoperative Nausea and Vomiting|date=2019|url=http://dx.doi.org/10.1016/b978-0-323-48110-6.00034-x|work=Pharmacology and Physiology for Anesthesia|pages=671–692|publisher=Elsevier|access-date=2023-01-05|last2=Gan|first2=Tong J.}}</ref>


== Chemistry and formulation<!-- Describe the chemistry and formulation of the drug. --> ==
== Chemistry and formulation<!-- Describe the chemistry and formulation of the drug. --> ==
Available in PO, intramuscular (IM), and intravenous (IV).


== History<!-- Describe the historical development of the drug. --> ==
== History<!-- Describe the historical development of the drug. --> ==


== References ==
== References ==
Zabirowicz, Eric S.; Gan, Tong J. (2019), "Pharmacology of Postoperative Nausea and Vomiting", ''Pharmacology and Physiology for Anesthesia'', Elsevier, pp.&nbsp;671–692, retrieved 2023-01-05<ref name=":1" />


Griddine, Alexandria; Bush, Jeffrey S. (2022), "Ondansetron", ''StatPearls'', Treasure Island (FL): StatPearls Publishing, [[PMID (identifier)|PMID]]&nbsp;29763014, retrieved 2023-01-05<ref name=":0" />
[[Category:Drug reference]]
[[Category:Drug reference]]

Revision as of 15:26, 5 January 2023

Ondansetron
Trade names

Zofran

Clinical data
Drug class

Anti-emetic

Uses

Prevention and treatment of chemo-induced, radiation induced nausea and vomiting, prevention of postoperative nausea and vomiting

Contraindications

Prolonged QT intervals, patients taking apomorphine

Routes of administration

PO, IM, IV

Dosage
Adult dosing
  • 4 mg IV
  • 2 mL of 2 mg/mL
Indication 
Postoperative nausea & vomiting
Route 
Preparation 
2 mg/mL

  • Maximum recommended daily dose 16 mg due to QT prolongation risk
    • Reduced to 8 mg in patients with severe hepatic impairment

  1. Griddine A, Bush JS. Ondansetron. [Updated 2022 Sep 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499839/
Pharmacodynamics
Mechanism of action

5HT3 antagonist

Adverse effects

cardiac arrhythmias, cardiac arrest, constipation, headaches

Pharmacokinetics
Metabolism

Liver oxidation followed by glucuronidation and sulfate conjugation

Elimination half-life

4 hours

Physical and chemical data
Article quality
Editor rating
Comprehensive
User likes
0

Ondansetron is a 5HT3 receptor antagonist that is commonly used for the treatment and prophylaxis of chemo induced nausea and vomiting, radiation induced nausea and vomiting, and postoperative nausea and vomiting.

Uses

  • treatment and prevention of chemo-induced nausea and vomiting
  • treatment and prevention of radiation induced nausea and vomiting
  • Prevention of postoperative nausea and vomiting
  • off-label use for the prevention of nausea and vomiting associated with pregnancy[1]

Contraindications

Absolute contraindications

  • Prolonged QT intervals
  • Patients taking apomorphine [1] as it can cause hypotension and loss of consciousness

Precautions

  • Maximum dose of 16 mg IV due to risk of QT prolongation and arrhythmias
  • Maximum dose decreased to 8 mg IV or 8 mg PO in severe hepatic impairment
  • Dissolving tablets formulations contain phenylalanine which can lead to irreversible neurological damage in phenylketonuria (PKU)[1]

Pharmacology

Pharmacodynamics

  • Metabolized by CYP2D6, CYP3A4, CYP2E1, CYP1A2 initially with oxidation followed by glucuronide and sulfate conjugations [1]
    • Many polymorphisms with four different phenotypes
      • Poor metabolizer (no functional allele)
      • Intermediate metabolizer (less activity than one functional allele)
      • Extensive metabolizer (two functional allele, most common phenotype)
      • Ultrarapid metabolizer (three functional allele)

Mechanism of action

  • Antagonism of the 5HT3 receptors
  • Centrally, ondansetron antagonizes the 5HT3 receptors in the area postrema [1]
  • Peripherally, ondansetron antagonizes the 5HT3 receptors on the vagus nerve within the GI tracts which forms synapses within the nucleus tracts solitarius (a region also responsible for vomiting)
    • Predominant mechanism for its anti-emetic effect

Adverse effects

  • Cardiac arrhythmia
  • Cardiac arrest
  • Constipation
  • Headache
  • dry mouth
  • malaise
  • drowsiness
  • sedation
  • pruritus
  • transient elevation in liver function test

Pharmacokinetics

  • Peak plasma concentration about 1.5 hours after an 8 mg PO dose
  • Plasma half life is approximately 4 hours[2]

Chemistry and formulation

Available in PO, intramuscular (IM), and intravenous (IV).

History

References

Zabirowicz, Eric S.; Gan, Tong J. (2019), "Pharmacology of Postoperative Nausea and Vomiting", Pharmacology and Physiology for Anesthesia, Elsevier, pp. 671–692, retrieved 2023-01-05[2]

Griddine, Alexandria; Bush, Jeffrey S. (2022), "Ondansetron", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 29763014, retrieved 2023-01-05[1]

  1. ↑ Jump up to: 1.0 1.1 1.2 1.3 1.4 1.5 Griddine, Alexandria; Bush, Jeffrey S. (2022), "Ondansetron", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 29763014, retrieved 2023-01-05
  2. ↑ Jump up to: 2.0 2.1 Zabirowicz, Eric S.; Gan, Tong J. (2019), "Pharmacology of Postoperative Nausea and Vomiting", Pharmacology and Physiology for Anesthesia, Elsevier, pp. 671–692, retrieved 2023-01-05

Top contributors: Cornel Chiu, Olivia Sutton and Chris Rishel

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