ZOFRAN AND DEXTROSE IN PLASTIC CONTAINER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZOFRAN AND DEXTROSE IN PLASTIC CONTAINER (ZOFRAN AND DEXTROSE IN PLASTIC CONTAINER).
Ondansetron is a selective serotonin 5-HT3 receptor antagonist. It blocks the action of serotonin at 5-HT3 receptors in the chemoreceptor trigger zone (CTZ) and gastrointestinal tract, thereby preventing nausea and vomiting. Dextrose provides caloric support.
| Metabolism | Ondansetron is extensively metabolized in the liver via hydroxylation, followed by glucuronide or sulfate conjugation. The major metabolic pathway involves CYP1A2, CYP2D6, and CYP3A4 enzymes. |
| Excretion | Primarily hepatic metabolism (~95%) via CYP1A2, CYP2D6, and CYP3A4; less than 10% excreted unchanged in urine. Fecal excretion accounts for ~20% of metabolites. |
| Half-life | Terminal elimination half-life is approximately 3–4 hours in adults, though may be prolonged to 5–8 hours in severe hepatic impairment (Child-Pugh class C) or elderly patients. |
| Protein binding | Approximately 70–76% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is approximately 1.9–2.4 L/kg, indicating extensive extravascular distribution. |
| Bioavailability | Not applicable for IV route; oral bioavailability is approximately 60% (due to first-pass metabolism). |
| Onset of Action | IV: Onset of antiemetic effect occurs within 1–2 minutes following intravenous administration. |
| Duration of Action | Duration of action is typically 4–8 hours, sufficient for prophylaxis of chemotherapy-induced nausea and vomiting for moderate emetogenic regimens. |
| Molecular Weight | 293.37 |
4 mg IV or IM every 8 hours as needed; for prevention of chemotherapy-induced nausea and vomiting, 0.15 mg/kg IV up to 16 mg per dose, infused over 15 minutes, given 30 minutes before chemotherapy, then repeat at 4 and 8 hours after first dose, or as a single 32 mg IV dose over 15 minutes immediately before chemotherapy.
| Dosage form | INJECTABLE |
| Renal impairment | No dosage adjustment required for renal impairment; however, patients with severe renal impairment (creatinine clearance < 30 mL/min) have modest increase in half-life, but no adjustment recommended. |
| Liver impairment | For Child-Pugh class A (mild): no adjustment. For Child-Pugh class B or C (moderate to severe): maximum daily dose of 8 mg (IV or oral) due to reduced clearance and increased half-life. |
| Pediatric use | For chemotherapy-induced nausea and vomiting: 0.15 mg/kg IV (maximum 16 mg per dose) given 30 minutes before chemotherapy, then at 4 and 8 hours after first dose. For postoperative nausea and vomiting: children 1 month to 12 years: 0.1 mg/kg IV (maximum 4 mg) as a single dose; children 12 years and older: 4 mg IV as a single dose. |
| Geriatric use | No specific dose adjustment required; pharmacokinetics similar to younger adults. Use caution with electrolyte abnormalities (e.g., hypokalemia, hypomagnesemia) due to potential QT prolongation. |
| 1st trimester | Ondansetron is not recommended in the first trimester due to a small increased risk of oral clefts; use only if clearly needed. |
| 2nd trimester | Limited data suggest no increased risk of major malformations; consider risk-benefit. |
| 3rd trimester | Use with caution near term due to risk of QT prolongation and potential neonatal effects; avoid during labor (may cause bradycardia). |
Clinical note
Comprehensive clinical and safety monograph for ZOFRAN AND DEXTROSE IN PLASTIC CONTAINER (ZOFRAN AND DEXTROSE IN PLASTIC CONTAINER).
| Placental transfer | Ondansetron crosses the placenta with cord blood levels approximately 40-60% of maternal levels. |
| Breastfeeding | Ondansetron is excreted into breast milk in small amounts with estimated infant dose <0.1% of maternal weight-adjusted dose. No adverse effects reported in breastfed infants. However, due to limited long-term data, use with caution in breastfeeding women, especially with high doses or prolonged therapy. |
■ FDA Black Box Warning
No FDA black box warning for this product.
| Serious Effects |
Hypersensitivity to ondansetron or any component of the formulationConcomitant use with apomorphine
| Precautions | Risk of QT prolongation and torsade de pointes, especially with concomitant use of other QT-prolonging drugs or electrolyte abnormalities, Hypersensitivity reactions, including anaphylaxis and bronchospasm, Serotonin syndrome when used with other serotonergic drugs, Masking of progressive ileus or gastric distension after abdominal surgery, Hepatic impairment reduces clearance; dose adjustment may be necessary |
| Food/Dietary | No specific food interactions. However, the dextrose component provides calories; monitor carbohydrate intake if diabetic. Avoid excessive consumption of foods or drinks that may cause nausea (e.g., strong odors, spicy foods) while on chemotherapy. |
Loading safety data…
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | First trimester: Limited human data; animal studies show no teratogenicity at clinically relevant doses. Second/third trimesters: No documented fetal abnormalities; use only if clearly needed. No known risk of congenital malformations based on available evidence. |
| Fetal Monitoring | Standard maternal monitoring via intravenous infusion rate and fluid balance (dextrose component). Fetal heart rate monitoring not routinely required; observe for maternal cardiac arrhythmias (QT prolongation risk) with ECG monitoring if cofactors present. |
| Fertility Effects | No evidence of impaired fertility or reproductive performance in animal studies. Human data insufficient to assess risk; no known adverse effect on human fertility. |
| Clinical Pearls | Ondansetron is a 5-HT3 antagonist that can cause QT prolongation; use ECG monitoring in patients with electrolyte abnormalities, CHF, or those on other QT-prolonging drugs. Do not exceed 16 mg single IV dose to avoid torsade risk. The dextrose component provides 3.4 kcal/g; monitor blood glucose in diabetic patients. Slow IV push over 2-5 minutes to minimize headache and dizziness. |
| Patient Advice | This medication prevents nausea and vomiting caused by chemotherapy, radiation, or surgery. · May cause headache, constipation, or dizziness; report palpitations or fainting (signs of irregular heartbeat). · Avoid sudden position changes to prevent dizziness from low blood pressure. · Do not take with other medications without doctor's approval, especially those affecting heart rhythm. · Inform your doctor if you have a history of heart problems, electrolyte disorders, or intestinal blockage. |