VELBAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VELBAN (VELBAN).
Inhibits microtubule polymerization by binding to tubulin, disrupting mitotic spindle formation and causing metaphase arrest in dividing cells.
| Metabolism | Primarily hepatic metabolism via CYP3A4; biliary excretion; small amount excreted renally. |
| Excretion | Primarily biliary/fecal (30-70% as unchanged drug and metabolites); renal excretion accounts for 10-25% of total clearance. |
| Half-life | Terminal elimination half-life is 24 to 30 hours in adults, with a longer terminal phase of up to 5 days due to enterohepatic recirculation; clinically, this supports a weekly dosing schedule. |
| Protein binding | Approximately 60-80% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein). |
| Volume of Distribution | 8-12 L/kg (adults), indicating extensive tissue distribution and binding to intracellular tubulin. |
| Bioavailability | Intravenous: 100% (only route); oral: <5% due to first-pass metabolism and P-glycoprotein efflux, not clinically used. |
| Onset of Action | Intravenous: antineoplastic effect onset is within 1-2 weeks (myelosuppression nadir at 7-10 days); oral: not applicable (IV only). |
| Duration of Action | Myelosuppression lasts 7-14 days, with recovery typically by day 21; antineoplastic effect duration varies with tumor type and response. |
IV: 0.1–0.15 mg/kg once weekly (not to exceed 10 mg per dose); alternatively, 3.5–6.5 mg/m² once weekly.
| Dosage form | INJECTABLE |
| Renal impairment | No specific adjustment recommended; use with caution in severe renal impairment (CrCl < 30 mL/min). |
| Liver impairment | Child-Pugh A: reduce dose by 50%; Child-Pugh B: reduce dose by 75%; Child-Pugh C: contraindicated. |
| Pediatric use | IV: 2.5–6.5 mg/m² once weekly, based on body surface area. |
| Geriatric use | No specific dose adjustment; monitor for neurotoxicity and myelosuppression due to age-related reduced clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VELBAN (VELBAN).
| Breastfeeding | Contraindicated during breastfeeding. Excreted into breast milk; M/P ratio not established. Potential for severe neonatal toxicity. |
| Teratogenic Risk | Category D. First trimester: high risk of fetal malformations including cranial, skeletal, and visceral defects. Second and third trimesters: risk of fetal growth restriction, oligohydramnios, and preterm birth. Avoid in pregnancy unless no alternative. |
| Fetal Monitoring |
■ FDA Black Box Warning
Vinblastine is for intravenous use only. Intrathecal administration is fatal. Severe granulocytopenia and other toxicities can occur. Must be administered under the supervision of a qualified physician experienced in cancer chemotherapy.
| Serious Effects |
Hypersensitivity to vinblastine or any component; severe leukopenia or granulocytopenia; active uncontrolled infection; intrathecal administration (fatal).
| Precautions | Bone marrow suppression (especially neutropenia); neurotoxicity (peripheral neuropathy, constipation, ileus); extravasation with tissue necrosis; pulmonary toxicity (bronchospasm, acute shortness of breath); hepatic impairment requires dose reduction; avoid in patients with severe infection; monitor liver function and CBC frequently. |
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| Monitor maternal blood counts, hepatic function, and renal function. Fetal monitoring: serial ultrasound for growth, amniotic fluid volume, and fetal anatomy; fetal heart rate monitoring. |
| Fertility Effects | May cause irreversible gonadal suppression leading to azoospermia or amenorrhea and premature ovarian failure. Fertility preservation consult recommended prior to treatment. |