# Vincristine: veterinary dose and monograph

> Vincristine is a veterinary drug. A vinca-alkaloid CHEMOTHERAPY agent dosed by BODY SURFACE AREA (mg/m²), not mg/kg. Indications include lymphoma / lymphoid leukaemia (multidrug CHOP-type protocols); transmissible venereal tumour (TVT) — often curative as monotherapy; immune-mediated thrombocytopenia (rapid platelet increase, adjunct). This monograph lists 4 reference doses for dogs, cats and horses, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/vincristine · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Veterinary drug
- **Also known as:** Oncovin, Vincristine sulphate, Cytocristin
- **Species with doses:** Dogs, Cats and Horses
- **Routes:** IV
- **Last reviewed:** 1 October 2026

## Indications

- Lymphoma / lymphoid leukaemia (multidrug CHOP-type protocols)
- Transmissible venereal tumour (TVT) — often curative as monotherapy
- Immune-mediated thrombocytopenia (rapid platelet increase, adjunct)
- Other vincristine-sensitive tumours (some sarcomas/carcinomas, per protocol)

## Vincristine dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Vincristine doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Lymphoma / transmissible venereal tumour | 0.5–0.75 mg/m² IV every 1–2 weeks (TVT: 0.5 mg/m², max 1 mg, weekly for 4–6 weeks) | IV | weekly (per protocol) | — |
| Immune-mediated thrombocytopenia (adjunct) | 0.02 mg/kg IV once (or 0.5–0.7 mg/m²) | IV | once (Papich: weekly with prednisolone) | — |

- Lymphoma / transmissible venereal tumour: Dosed by BODY SURFACE AREA. Papich 5e: 0.5–0.75 mg/m² (or 0.025–0.05 mg/kg) IV once weekly. Plumb’s p.1168: 0.5–0.75 mg/m² IV every 1–2 weeks in combination protocols; TVT as sole therapy 0.5 mg/m² (max 1 mg) weekly for 4–6 weeks. Strict IV technique — vesicant. Consult an oncologist.
- Immune-mediated thrombocytopenia (adjunct): Plumb’s p.1168: 0.5 mg/m² IV when platelets <10–20,000/µL or bleeding (Saxon); 0.5–0.7 mg/m² bolus or 4–6 h infusion if refractory to prednisone (Trepanier); 0.02 mg/kg IV once (Cohn). Papich 5e: 0.02 mg/kg IV once a week with prednisolone.

### Cats

*Vincristine doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Lymphoma (per protocol) | 0.5–0.75 mg/m² IV every 1–3 weeks | IV | every 1–3 weeks (per protocol) | — |

- Lymphoma (per protocol): Dosed by BODY SURFACE AREA. Papich 5e: dogs and cats 0.5–0.75 mg/m² IV weekly. Plumb’s p.1168: cats 0.5–0.75 mg/m² IV every 1–3 weeks. Vesicant; consult an oncologist.

### Horses

*Vincristine doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Lymphoma (CAP protocol adjunct) | 0.5 mg/m² IV weekly (usually 2.5–3 mg total per horse) | IV | weekly | — |

- Lymphoma (CAP protocol adjunct): Plumb’s p.1168 (Mair & Couto 2006): 0.5 mg/m² IV weekly, added to the cytarabine/cyclophosphamide/prednisolone protocol if there is no response. Oncologist input recommended.

## Contraindications

Pre-existing significant myelosuppression (neutropenia), severe hepatic impairment (hepatic clearance — reduce dose), and peripheral neuropathy. Perivascular administration (vesicant — necrosis). Pregnancy. Known hypersensitivity. Intrathecal use is FATAL (IV only).

## Species-specific warnings

> **Caution:** Cats: Small body size makes BSA dosing error-prone — calculate carefully; cats may be sensitive to GI and marrow toxicity.

## Adverse effects

- Myelosuppression (neutropenia — usually milder than other chemo agents)
- GI: vomiting, diarrhoea, anorexia, ileus (constipation)
- Peripheral neuropathy (dose-related)
- Severe tissue necrosis if extravasated (vesicant)
- Alopecia (in continuously growing coats)

## Drug interactions

- Other myelosuppressive chemo: additive marrow suppression (built into protocols)
- CYP3A inhibitors (azoles, macrolides): raise vincristine levels → increased toxicity
- Drugs causing neuropathy: additive peripheral neurotoxicity
- L-asparaginase: timing affects vincristine clearance (give vincristine first per protocol)

## Pregnancy and lactation

Contraindicated in pregnancy (cytotoxic/teratogenic). Handle with cytotoxic precautions; pregnant staff should not handle/administer.

## Monitoring

- CBC before each dose (neutrophil count — delay/reduce if neutropenic)
- IV catheter placement/patency (clean stick; vesicant) and the site afterwards
- GI signs (ileus/constipation) and peripheral neuropathy
- Tumour response (e.g. TVT regression); cumulative dose

## Toxicity and overdose

Dose-limiting toxicities are myelosuppression (neutropenia nadir), GI toxicity (including ileus/constipation), and peripheral neuropathy. EXTRAVASATION is a major hazard — severe, progressive tissue necrosis. Accidental intrathecal administration is fatal. Overdose intensifies all of these.

Management: No specific antidote. Supportive/intensive care: manage neutropenic sepsis (antibiotics, ± G-CSF), GI support, and neuropathy. For EXTRAVASATION: stop, aspirate, apply WARM compresses and (per oncology guidance) consider hyaluronidase infiltration; do not use cold. Monitor CBC closely; severe overdose has a guarded prognosis.

## Clinical pearls

- Dose by BODY SURFACE AREA (mg/m²), not mg/kg — and double-check the calculation; it is a cytotoxic with a narrow margin
- The drug of choice for TVT — often curative in a few weekly doses as a single agent
- A clever adjunct in immune-mediated thrombocytopenia: it transiently boosts platelet counts
- VESICANT — a perfect, single-stick IV is essential; extravasation causes devastating necrosis (warm compress + hyaluronidase if it happens)
- Generally less myelosuppressive than other chemo agents, but still check the CBC before every dose; handle with full cytotoxic precautions

## Mechanism of action

Binds tubulin and inhibits microtubule polymerisation, arresting the mitotic spindle in metaphase so dividing (cancer) cells cannot complete mitosis and undergo apoptosis — cell-cycle (M-phase) specific cytotoxicity. Its effect on megakaryocyte microtubules is thought to underlie the platelet release used in immune-mediated thrombocytopenia.

## Formulations and products

- Injection 1 mg/mL
- Oncovin / Vincristine — 1 mg/mL (1 / 2 mg vial), Injection (human-label)
- Cytocristin — 1 mg / 2 mg vial, Injection (human-label)

## Storage

Injection: REFRIGERATE (2–8 °C), protect from light. Handle as a hazardous cytotoxic drug (closed-system/gloves/PPE); dispose appropriately.

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Vincristine for dogs?

Reference doses for Vincristine in dogs: 0.5–0.75 mg/m² IV every 1–2 weeks (TVT: 0.5 mg/m², max 1 mg, weekly for 4–6 weeks) IV weekly (per protocol) (Lymphoma / transmissible venereal tumour); 0.02 mg/kg IV once (or 0.5–0.7 mg/m²) IV once (Papich: weekly with prednisolone) (Immune-mediated thrombocytopenia (adjunct)). Confirm against the label and the patient before use.

### What is the dose of Vincristine for cats?

Reference doses for Vincristine in cats: 0.5–0.75 mg/m² IV every 1–3 weeks IV every 1–3 weeks (per protocol) (Lymphoma (per protocol)). Confirm against the label and the patient before use.

### What is the dose of Vincristine for horses?

Reference doses for Vincristine in horses: 0.5 mg/m² IV weekly (usually 2.5–3 mg total per horse) IV weekly (Lymphoma (CAP protocol adjunct)). Confirm against the label and the patient before use.

### When should Vincristine not be used?

Pre-existing significant myelosuppression (neutropenia), severe hepatic impairment (hepatic clearance — reduce dose), and peripheral neuropathy. Perivascular administration (vesicant — necrosis). Pregnancy. Known hypersensitivity. Intrathecal use is FATAL (IV only).

### What are the side effects of Vincristine in animals?

Myelosuppression (neutropenia — usually milder than other chemo agents); GI: vomiting, diarrhoea, anorexia, ileus (constipation); Peripheral neuropathy (dose-related); Severe tissue necrosis if extravasated (vesicant); Alopecia (in continuously growing coats).

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.