| name | Ondansetron |
| classification | 5-HT3 receptor antagonist |
| pharmacokinetics | Ondansetron is rapidly absorbed after oral or intravenous administration. Peak plasma concentrations are reached within 1-2 hours after oral administration. The drug is extensively metabolized in the liver primarily via cytochrome P450 3A4. The elimination half-life is approximately 2-4 hours. Renal elimination is a minor route of elimination. |
| suggested dosage | | adult | | oral | 8 mg every 8 hours as needed or 32 mg every 12 hours pre-emptively | | IV | 4 mg intravenously, every 8-24 hours as needed, with a maximum total daily dose of 16mg. |
| | notes | Dosage should be adjusted based on individual patient response and severity of nausea and vomiting. Consult a healthcare professional for specific dosage recommendations tailored to the individual patient. |
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| indications | Ondansetron is primarily used to prevent and treat nausea and vomiting associated with various conditions, including chemotherapy-induced nausea and vomiting (CINV), postoperative nausea and vomiting, and radiation-induced nausea and vomiting. It is also used to treat nausea and vomiting associated with other conditions like migraine, gastroenteritis, and viral illnesses. |
| safety in pregnancy | Ondansetron is generally considered safe for use during pregnancy, but it's important to discuss the risks and benefits with a healthcare professional, especially during the first trimester. Limited data exists regarding long-term effects on the fetus. |
| safety in breastfeeding | Limited data exists on the excretion of ondansetron in breast milk. Weigh the potential benefits of treatment against potential risks to the infant. Consult a healthcare professional for guidance. |
| side effects | | 1 | Headache | | 2 | Constipation | | 3 | Diarrhea | | 4 | Dizziness | | 5 | Fatigue | | 6 | Drowsiness | | 7 | Nausea | | 8 | Vomiting | | 9 | Dry mouth | | 10 | Abdominal pain | | 11 | Changes in heart rate | | 12 | Elevated blood pressure | | 13 | Rash |
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| alternatives | |
| contraindications | | 1 | Hypersensitivity to ondansetron or other components of the medication | | 2 | History of severe cardiac events or problems |
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| interactions | | 1 | | drug | Cytochrome P450 3A4 inhibitors (e.g., ketoconazole, erythromycin) | | effect | May increase ondansetron levels, leading to increased risk of side effects. |
| | 2 | | drug | Cytochrome P450 3A4 inducers (e.g., rifampicin, phenytoin) | | effect | May decrease ondansetron levels, reducing effectiveness. |
| | 3 | | drug | Drugs that prolong the QT interval (some anti-arrhythmics, some antidepressants) | | effect | Possible increase in the risk of QT prolongation |
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| warnings and precautions | | 1 | Monitor for signs of QT prolongation (prolonged heart rhythm) | | 2 | Use with caution in patients with liver impairment | | 3 | Use with caution in patients with a history of heart problems | | 4 | Monitor for any unusual or worsening symptoms | | 5 | Avoid concurrent use with other medications that can worsen certain side effects |
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| additional information | Ondansetron is available in various formulations. Always follow the prescribed dosage and administration instructions. |
| patient specific considerations | | age | No significant age-related dosage adjustments are typically necessary for ondansetron. | | weight | No significant weight-related dosage adjustments are typically necessary for ondansetron. |
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