Vincristine !

Vinca alkaloid that blocks the mitotic spindle. Key in childhood leukaemia and lymphoma; it injures nerves, spares the marrow, is fatal given intrathecally.

Updated 2026-11-01

Class: Microtubule inhibitors
Target: β-tubulin (vinca site, at the junction between tubulin dimers)
ATC code: L01CA02
WHO Model List of Essential Medicines

β-tubulin (vinca site, at the junction between tubulin dimers)Vincristine

The figure shows vinblastine, which occupies the same vinca site, bound to bovine tubulin; no vincristine–tubulin structure is available.

Target in 3D: β-tubulin (vinca site, at the junction between tubulin dimers). PDB structure 5J2T (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Vincristine binds β-tubulin at the vinca site and stops tubulin dimers from adding to microtubules. Without a mitotic spindle, dividing cells arrest in metaphase and die. Nerve axons also depend on microtubules to transport material, so the same action causes a dose-related sensory, motor and autonomic neuropathy.

Vincristine binds tubulin at the vinca site
Microtubules cannot assemble: no spindle
Cells arrest in metaphase and die
Axonal transport fails too: neuropathy

Pharmacokinetics

Absorption: Intravenous only.
Distribution: Leaves the blood quickly and binds tightly in tissues; enters the cerebrospinal fluid poorly.
Metabolism: Liver, by CYP3A; also a P-glycoprotein substrate.
Elimination: Mostly in the faeces (bile); a smaller part in the urine.
Half-life: Long terminal half-life, about 85 hours on average, varying widely between people.

Indications

Acute leukaemia.
Hodgkin and non-Hodgkin lymphoma, in combination.
Rhabdomyosarcoma, neuroblastoma and Wilms tumour, in combination.

Adverse effects

Common

Hair loss (the most common effect)
Constipation and abdominal cramps
Tingling and numbness, loss of tendon reflexes, foot drop
Jaw, throat and bone pain
Urinary retention from bladder atony

Contraindications

Demyelinating form of Charcot–Marie–Tooth disease
Any route other than intravenous

Key interactions

Strong CYP3A inhibitors (e.g. itraconazole); moderate ones such as fluconazole: Earlier and more severe neurotoxicity; strong inhibitors are avoided.
Strong CYP3A inducers (e.g. St John's wort) and P-glycoprotein inhibitors or inducers: Change vincristine exposure; avoided.
Phenytoin: Chemotherapy combinations with vincristine have lowered phenytoin levels and increased seizures.
Mitomycin: Acute bronchospasm and breathlessness occur most often with this combination.
Live vaccines: Not recommended during treatment.

What is monitored

Neurological examination: sensation, reflexes, gait, hoarseness
Bowel movements and abdominal examination
Sodium (SIADH) and blood counts in combination regimens
Liver tests, especially in children

Administration and safety

Intravenous use only: given intrathecally it is usually fatal. The bag is labelled «for intravenous use only – fatal if given by other routes».
Dispensed diluted in a flexible plastic container, which lowers the risk of a fatal wrong-route error.
Vesicant: if leakage occurs, the injection is stopped and the rest given in another vein; local hyaluronidase and moderate heat help disperse the drug.
Mixed only with normal saline (sodium chloride); the needle position is confirmed before injecting.
Hazardous drug: prepared and given following hazardous-drug handling procedures (impervious gloves, no skin contact) and disposed of as cytotoxic waste.

Nursing care

Before giving it, confirm the route is intravenous with a second nurse; it is never taken to a lumbar puncture or intrathecal procedure.
Bowel regimen from the start (fluids, fibre, stool softeners); ask about stools every day and report abdominal pain or no bowel movement.
Ask about tingling, weakness, trouble walking or buttoning, jaw pain and hoarseness before each dose.
Check that the patient is passing urine normally.
Avoid eye contact with the drug; if it happens, rinse the eye immediately and thoroughly.

Pregnancy and breastfeeding

Can cause fetal harm; pregnancy is avoided during treatment.

Test yourself

Think of the answer, then tap the question to see it.

What is the dose-limiting toxicity of vincristine?

Neurotoxicity: peripheral neuropathy, constipation and ileus, cranial nerve palsies. Marrow suppression is minor.

Why is vincristine dispensed diluted in a flexible plastic container labelled for intravenous use only?

To prevent a fatal wrong-route error: intrathecal vincristine is usually fatal.

A child on vincristine has colicky abdominal pain and an empty rectum. What should be suspected?

Constipation with upper-colon impaction or paralytic ileus from vincristine's autonomic neurotoxicity.

Which antifungals raise vincristine toxicity, and why?

Azoles such as itraconazole (and fluconazole) inhibit CYP3A, which metabolises vincristine, so neurotoxicity comes earlier and is more severe.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - VINCRISTINE SULFATE injection, solution (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 70 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).

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Representative model, for educational purposes only.