Oncovin

Generic Name: Vincristine sulfate
Product Name: Oncovin

Indication

Indications for use of Oncovin include:

Acute leukaemia

Children with neuroblastoma, osteogenic sarcoma, Ewing’s sarcoma, rhabdomyosarcoma, Wilms’ tumour, Hodgkin’s disease, non-Hodgkin’s lymphomas, embryonal carcinoma of the ovaries, and rhabdomyosarcoma of the uterus.

Idiopathic thrombocytopaenic purpura resistant to other treatments (splenectomy and short-term treatment with adrenocortical steroids).

NB: Oncovin is not the recommended first line treatment for idiopathic thrombocytopaenic purpura. Cancer chemotherapy usually involves the simultaneous use of several medications with different side effects and mechanisms of action.

Oncovin is often chosen because it does not significantly suppress the bone marrow at recommended doses and its toxic effect is unique (at toxic doses Oncovin causes dysfunction of peripheral nerves to the hands and feet).

Action

The action of Oncovin is not yet fully understood. It causes mitotic arrest in in vitro cancer cells (It prevents cancer cells in test tubes from being able to reproduce effectively). Clinical evidence shows that Oncovin does not penetrate cerebrospinal fluid (the fluid surrounding the brain and spinal cord) very well.

Dose advice

Oncovin should only be administered by health practitioners who are experienced in the use of Oncovin and other chemotherapeutic agents and should only be administered intravenously (into a vein via a drip or injection) and is usually given weekly. If Oncovin should not be injected directly into an intrathecal reservoir (device inside the skull that delivers medications into the fluid surrounding the brain and spinal cord) as this may cause death.

Nerve damage by Oncovin appears to be related to the amount of Oncovin given, that is, the more Oncovin given, the greater the risk of damage to the peripheral nerves. Exact calculation and administration of dosages is important, as overdosage may be fatal. Children are usually given 2 mg/m2. Children weighing 10 kg or less, should commence treatment with a dose of 0.05 mg/kg once weekly. The usual dose for adults is 1.4 mg/m2, reduced by 50% if the patient has a certain abnormal liver function test (absolute bilirubin above 3 mg/100 mL).

It is important to ensure that the intravenous cannula through which the medication is to be given is properly positioned in the vein prior to injection of Oncovin. Leakage into the surrounding tissues may cause considerable irritation and if leakage occurs the injection should be discontinued immediately, and a different vein should be chosen for administration of the remaining dose.

A doctor may inject another medication called hyaluronidase and apply warmth to the area of leakage to help disperse the drug and minimises discomfort and inflammation. Patients receiving Oncovin for idiopathic thrombocytopaenic purpura will usually receive weekly doses of Oncovin for three to four weeks with the aim of achieving remission. If patients fail to respond after three to six doses, it is unlikely that they will respond to subsequent doses.

Schedule

Schedule 4

Common side effects

Discussing the possibility of adverse effects with your doctor is highly recommende. The side effects of Oncovin are generally reversible and are related to the amount of the drug being administered.

Common side effects include:

Hair loss
Rash
Fever
Headache
Constipation: Routine medications for the prevention of constipation are recommended.
Other gastrointestinal side effects, such as: cramp, weight loss, nausea, vomiting, ulcers, diarrhoea and anorexia.
Altered consciousness and psychological changes eg. depression, agitation, inability to sleep and hallucinations.
A sequence of neuromuscular side effects (related to nerves and muscles) beginning with loss of sensation. This may progress to loss of power in some muscles, pain and difficulty moving certain muscles. These effects may be irreversible (not curable), and a decision may be made to stop the medication if these side effects present problems. Patients suffering from disorders of the nervous system or muscles before commencing Oncovin therapy may experience worsening of their condition after commencing treatment.
Changes in blood pressure (may become higher or lower)

Uncommon side effects

Some cases of patients being treated with Oncovin suffering from convulsions and high blood pressure have been reported.
Convulsions are more common in children and may be followed by coma.
Temporary blindness and optic atrophy with blindness.
Vestibular and auditory damage to the eighth cranial nerve (very rare) resulting in partial or total deafness (temporarily or permanent), balancing difficulties, dizziness, vertigo and a disturbance of eye movement called nystagmus. Please inform your doctor of all other medications you take regularly before commencing Oncovin treatment, as some other medications may increase the risk of these side effects occurring.
Hypersensitivity – anaphylaxis, rash and oedema
Paralytic ileus (the digestion of food ceases due to temporary paralysis of the muscle in the wall of the intestine), particularly in children and in the elderly
Perforation of the bowel
Necrosis (tissue death) of the bowel
Retention of urine
Polyuria (urinating frequently)
Dysuria (pain when urinating)
Patients who have been treated with mediastinal radiation prior to Oncovin therapy are at greater risk of developing coronary artery disease and myocardial infarction (heart attack).
Anaemia (low red blood cell count), leucopenia (low white blood cell count) and thrombocytopenia (deficiency of the cells that help to stop bleeding)
Other symptoms related to nervous system disorders.
Defective sweating
Muscular jerks
Abnormal swallowing
Impotence
Loss of libido
SIADH (Syndrome of Inappropriate Antidiuretic Hormone secretion) relates to hormonal, electrolyte and fluid balance disturbances in the body.