vinblastine sulfate (VLB)
Velban, Velbe ◆

Available forms
Available by prescription only
Injection: 10-mg vials (lyophilized powder), 1 mg/ml in 10-ml and 25-ml vials

Indications and dosages
  Dosage and indications may vary. Check current literature for recommended protocol.
 Breast or testicular cancer, Hodgkin’s and malignant lymphomas, choriocarcinoma, lymphosarcoma, neuroblastoma, lung cancer, mycosis fungoides, histiocytosis, Kaposi’s sarcoma. Adults: 0.1 mg/kg or 3.7 mg/m² I.V. weekly or q 2 weeks. May be increased in weekly increments of 50 mcg/kg or 1.8 to 1.9 mg/m² to maximum dose of 0.5 mg/kg or 18.5 mg/m² I.V. weekly, based on response. Dose shouldn’t be repeated if WBC count falls below 4,000/mm³.
Children: 2.5 mg/m² I.V. as a single dose every week, increased weekly in increments of 1.25 mg/m² to maximum of 12.5 mg/m².

Pharmacodynamics
Antineoplastic action: Exerts cytotoxic activity by arresting the cell cycle in the metaphase portion of cell division, resulting in a blockade of mitosis. Drug also inhibits DNA-dependent RNA synthesis and interferes with amino acid metabolism, inhibiting purine synthesis.

Pharmacokinetics
Absorption: Administered I.V.
Distribution: Distributed widely into body tissues. Drug crosses blood-brain barrier but doesn’t achieve therapeutic levels in CSF.
Metabolism: Metabolized partially in liver to an active metabolite.
Excretion: Excreted primarily in bile as unchanged drug. Smaller portion excreted in urine. Triphasic plasma elimination; half-lives of 3.7 minutes, 1.6 hours, and 24.8 hours for alpha, beta, and terminal phases, respectively.

Contraindications and precautions
Contraindicated in patients with severe leukopenia, granulocytopenia (unless result of disease being treated), or bacterial infection. Use cautiously in patients with hepatic dysfunction.

Interactions
Drug-drug. Erythromycin: May cause vinblastine toxicity. Watch closely for toxicity.
Mitomycin: Causes acute shortness of breath and severe bronchospasm. Use cautiously together.
Phenytoin: May reduce plasma phenytoin levels. Increase phenytoin dosage, as needed.

Adverse reactions
CNS: depression, paresthesia, peripheral neuropathy and neuritis, numbness, loss of deep tendon reflexes, muscle pain and weakness, seizures, CVA, headache.
CV: hypertension, MI.
EENT: pharyngitis.
GI: nausea, vomiting, ulcer, bleeding, constipation, ileus, anorexia, diarrhea, abdominal pain, stomatitis.
Hematologic: anemia, leukopenia (nadir occurs days 4 to 10 and lasts another 7 to 14 days), thrombocytopenia.
Metabolic: hyperuricemia, weight loss.
Respiratory: acute bronchospasm, shortness of breath.
Skin: vesiculation, reversible alopecia; irritation, phlebitis, cellulitis, necrosis with extravasation.

Effects on lab test results
• May increase uric acid levels.
• May decrease hemoglobin and WBC and platelet counts.

Overdose and treatment
Signs and symptoms of overdose include stomatitis, ileus, mental depression, paresthesia, loss of deep reflexes, permanent CNS damage, and myelosuppression.
 Treatment is usually supportive and includes transfusion of blood components and appropriate symptomatic therapy.

Special considerations
• Give an antiemetic before drug to reduce nausea.
• Drug may be given by I.V. push injection over 1 minute into the tubing of a freely flowing I.V. infusion.
• Dilution into larger volume isn’t recommended for infusion into peripheral veins. This method increases risk of extravasation. Drug may be administered as an I.V. infusion through a central venous catheter.
• Don’t administer more often than every 7 days to allow review of effect on leukocytes before next dose. Leukopenia may develop.
• Reduced dosages may be needed in patients with liver disease.
• Prevent uric acid nephropathy with generous oral fluid intake and administration of allopurinol.
 ALERT Don’t confuse vinblastine with vincristine, vindesine, or vinorelbine.
• Drug is less neurotoxic than vincristine.
 ALERT Watch for life-threatening acute bronchospasm reaction. This reaction is most likely to occur in patients also receiving mitomycin.
Breast-feeding patients
• It isn’t known if drug appears in breast milk. However, because of risk of serious adverse reactions, mutagenicity, and carcinogenicity in infants, breast-feeding isn’t recommended.
Geriatric patients
• Patients with cachexia or skin ulceration (which is more common in elderly patients) may be more susceptible to leukopenic effect of drug.

Patient education
• Encourage adequate fluid intake to increase urine output and facilitate excretion of uric acid.
• Reassure patient that therapeutic response isn’t immediate. Adequate trial is 12 weeks.
• Advise patient to avoid exposure to people with infections and to report signs of infection or unusual bleeding immediately.
• Reassure patient that hair should grow back after treatment has ended.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use