Difference between revisions of "Ondansetron"
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Patients taking apomorphine | Patients taking apomorphine | ||
| routes = PO, IM, IV | | routes = PO, IM, IV | ||
| dosage = | | dosage = | ||
| dosage_calculation = ondansetron | | dosage_calculation = ondansetron | ||
| mechanism = 5HT3 antagonist | | mechanism = 5HT3 antagonist | ||
Latest revision as of 12:36, 8 January 2023
Ondansetron
| Trade names |
Zofran |
|---|---|
| Clinical data | |
| Drug class |
Antiemetic |
| Uses |
Prevention and treatment of postoperative nausea and vomiting |
| Contraindications |
Prolonged QT interval 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 | |
| User likes | 0 |
Ondansetron is a 5HT3 receptor antagonist that is commonly used for the prevention and treatment of postoperative nausea and vomiting.
Uses
- Prevention and treatment of postoperative nausea and vomiting
- Commonly used to treat many other causes of nausea and vomiting[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
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 [1]
- 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]
- 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)
- Many polymorphisms with four different phenotypes
Chemistry and formulation
Available in PO, intramuscular (IM), and intravenous (IV).
History
References
- ↑ 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
- ↑ 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