This preparation is for intravenous use only. It should be administered by individuals experienced in the administration of vincristine sulfate injection. The intrathecal administration of vincristine sulfate injection usually results in death.
To reduce the potential for fatal medication errors due to incorrect route of administration, Vincristine sulfate injection should be diluted in a flexible plastic container and prominently labeled as indicated "FOR INTRAVENOUS USE ONLY – FATAL IF GIVEN BY OTHER ROUTES."
See OVERDOSAGE section for the treatment of patients given intrathecal Vincristine Sulfate Injection, USP.
Vincristine sulfate can cause fetal harm when administered to a pregnant woman. When pregnant mice and hamsters were given doses of vincristine sulfate that caused resorption of 23% to 85% of fetuses, fetal malformations were produced in those that survived. Five monkeys were given single doses of vincristine sulfate between days 27 and 34 of their pregnancies; 3 of the fetuses were normal at term, and 2 viable fetuses had grossly evident malformations at term. In several animal species, vincristine sulfate can induce teratogenesis as well as embryo death at doses that are nontoxic to the pregnant animal. There are no adequate and well–controlled studies in pregnant women. If this drug is used during pregnancy or if the patient becomes pregnant while receiving this drug, she should be apprised of the potential hazard to the fetus. Women of child–bearing potential should be advised to avoid becoming pregnant.
Acute uric acid nephropathy, which may occur after the administration of oncolytic agents, has also been reported with vincristine sulfate. In the presence of leukopenia or a complicating infection, administration of the next dose of vincristine sulfate injection warrants careful consideration.
If central nervous system leukemia is diagnosed, additional agents may be required, because vincristine does not appear to cross the blood–brain barrier in adequate amounts.
Particular attention should be given to dosage and neurologic side effects if vincristine sulfate injection is administered to patients with preexisting neuromuscular disease and when other drugs with neurotoxic potential are also being used.
Acute shortness of breath and severe bronchospasm have been reported following the administration of vinca alkaloids. These reactions have been encountered most frequently when the vinca alkaloid was used in combination with mitomycin–C and may require aggressive treatment, particularly when there is preexisting pulmonary dysfunction. The onset of these reactions may occur minutes to several hours after the vinca alkaloid is injected and may occur up to 2 weeks following the dose of mitomycin. Progressive dyspnea requiring chronic therapy may occur. Vincristine sulfate should not be readministered.
Care must be taken to avoid contamination of the eye with concentration of vincristine sulfate injection used clinically. If accidental contamination occurs severe irritation (or, if the drug was delivered under pressure, even corneal ulceration) may result. The eye should be washed immediately and thoroughly.
Because dose–limiting clinical toxicity is manifested as neurotoxicity clinical evaluation (e.g., history, physical examination) is necessary to detect the need for dosage modification. Following administration of vincristine sulfate injection, some individuals may have a fall in the white blood cell count or platelet count, particularly when previous therapy or the disease itself has reduced bone–marrow function. Therefore, a complete blood count should be done before administration of each dose. Acute elevation of serum uric acid may also occur during induction of remission in acute leukemia; thus, such levels should be determined frequently during the first 3 to 4 weeks of treatment or appropriate measures taken to prevent uric acid nephropathy. The laboratory performing these tests should be consulted for its range of normal values.
The simultaneous oral or intravenous administration of phenytoin and antineoplastic chemotherapy combinations that included vincristine sulfate has been reported to reduce blood levels of the anticonvulsant and to increase seizure activity. Dosage adjustment should be based on serial blood level monitoring. The contribution of vincristine sulfate to this interaction is not certain. The interaction may result from reduced absorption of phenytoin and an increase in the rate of its metabolism and elimination.
Vincristine sulfate is a substrate for cytochrome P450 3A isozymes (CYP3A). Concurrent administration of vincristine sulfate with itraconazole or fluconazole (known inhibitors of the CYP3A metabolic pathway) has been reported to cause an earlier onset and/or an increased severity of neuromuscular side effects (see ADVERSE REACTIONS). This interaction is presumed to be related to inhibition of the metabolism of vincristine. Therefore, the concomitant use of strong CYP3A inhibitors with vincristine sulfate should be avoided. Patients should be frequently monitored for adverse reactions with concomitant use of moderate CYP3A inhibitors (e.g., fluconazole) with vincristine sulfate.
Concurrent use of strong CYP3A inducers (e.g., St. John's Wort) with vincristine sulfate should be avoided.
Vincristine sulfate is also a substrate for P-glycoprotein (P-gp). Therefore, the concomitant use of P-gp inhibitors or inducers should be avoided.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Neither in vivo nor in vitro laboratory tests have conclusively demonstrated the mutagenicity of this product. Fertility following treatment with vincristine sulfate alone for malignant disease has not been studied in humans. Clinical reports of both male and female patients who received multiple–agent chemotherapy that included vincristine sulfate indicate that azoospermia and amenorrhea can occur in postpubertal patients. Recovery occurred many months after completion of chemotherapy in some but not all patients. When the same treatment is administered to prepubertal patients, permanent azoospermia and amenorrhea are much less likely.
Patients who received chemotherapy with vincristine sulfate in combination with anti–cancer drugs known to be carcinogenic have developed second malignancies. The contributing role of vincristine sulfate in this development has not been determined. No evidence of carcinogenicity was found following intraperitoneal administration of vincristine sulfate in rats and mice, although this study was limited.
Usage in Pregnancy
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions due to vincristine sulfate in nursing infants, a decision should be made either to discontinue nursing or the drug, taking into account the importance of the drug to the mother.
See DOSAGE AND ADMINISTRATION section.