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(Brief summary, Uses, contraindication, precautions, pharmacodynamics, adverse effects, chemistry and formulation, references)
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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
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. 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. 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