Vincristine

Source and Pharmacology

Vincristine (also called Vincristine Sulfate, VCR, Oncovin, NSC #067574) is an alkaloid isolated from Vinca rosea (periwinkle). It is lethal for normal and tumor cells during the S phase and binds microtubules, causing arrest of cell division in metaphase. Its serum decay pattern is triphasic, with initial, middle and terminal half-lives of 5 minutes, 80 minutes, and 85 minutes, respectively. It is excreted in the bile and feces. CSF penetration is poor.

Toxicity

Onset

Common

Happens to 21-100 out of every 100 children treated

Occasional

Happens to 5-20 out of every 100 children treated

Rare

Happens to <5 out of every 100 children treated
Immediate

Within 1-2 days of getting the drug

 Local ulceration if extravasated Jaw pain
Prompt

Within 2-3 weeks, prior to next cycle

 Hair loss (L) Weakness, constipation Paralytic ileus, vocal cord paralysis, ptosis, myelosuppression, inappropriate ADH, CNS depression, seizure
Delayed

Any time later during therapy, excluding the above conditions

 Loss of deep tendon reflexes Numbness, tingling and clumsiness
Late

Post-treatment
Unknown Frequency and Timing Fetal toxicities and teratogenic effects of vincristine, either alone or in combination with other antineoplastic agents, have been noted in humans that received vincristine during pregnancy. The toxicities include chromosome abnormalities, malformation, pancytopenia and low birth weight. Fetal toxicities and teratogenic effects of vincristine are not long-term effects.

(L) = Toxicity may also occur later.

 

Formulation and Stability

Available in solutions of 1 mg/mL in 1, 2, or 5 mL vials. Refrigerate and protect from light. Once opened, vincristine should be refrigerated and used within 10 days. Note that vincristine is light-sensitive.

Guidelines for Administration

Give by intravenous push over <1 minute. Special Precautions: Avoid extravasation. Of note, the Toronto Protocol already uses the lower vincristine dose of 0.05 mg/kg to avoid CSA-accentuation of vincristine neurotoxicity, so that the usual dose reduction for infants is not necessary [McLeod 1994]. Furthermore, all patients only receive 0.025 mg/kg of vincristine in Cycle 1 in case of unexpectedly severe neurotoxicity due to CSA accentuating the effects of vincristine [Schinkel 1994]. If no unexceptable toxicity is seen with the first cycle, the vincristine will be given at the usual dose of 0.05 mg/kg for all subsequent cycles.

Drug Procurement

Vincristine is commercially available. See the package insert for further information.

 


 

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