| In general, adverse reactions are reversible and are related to dosage size and cumulative dosage. The use of small amounts of vincristine daily for long periods is not advised. The most common adverse reaction is alopecia; the most troublesome adverse reactions are neuromuscular in origin.When single weekly doses of vincristine are employed, the adverse reactions of leucopenia, neuritic pain, and constipation are usually of short duration (i.e. less than 7 days). When the dosage is reduced, these reactions may lessen or disappear. They seem to be increased when the calculated amount of medicinal product is given in divided doses. Other adverse reactions, such as alopecia, sensory loss, paraesthesia, difficulty in walking, slapping gait, loss of deep-tendon reflexes and muscle wasting may persist for at least as long as therapy is continued. Generalised sensorimotor dysfunction may become progressively more severe with continued treatment, but the neuromuscular difficulties may persist for prolonged periods in some patients. Re-growth of hair may occur while maintenance therapy continues.The following adverse reactions have been reported:Blood and lymphatic system disorders: Leucopenia; vincristine does not appear to have any constant or significant effect upon the platelets or the red blood cells, however, anemia and thrombocytopenia have been reported. If thrombocytopenia is present when treatment with vincristine sulphate is begun, it may actually improve before the appearance of marrow remission. Endocrine disorders: Rare occurrences of a syndrome attributable to inappropriate anti-diuretic hormone secretion have been observed in patients treated with vincristine. There is a high urinary sodium excretion in the presence of hyponatraemia; renal or adrenal disease, hypotension, dehydration, azotaemia and clinical oedema are absent. With fluid deprivation, improvement occurs in the hyponatraemia and in the renal loss of sodium.Nervous system disorders (often dose limiting): Neuritic pain, sensory loss, paraesthesiae, difficulty in walking, slapping gait, loss of deep tendon reflexes, ataxia, paresis, foot drop and cranial nerve palsies, especially ocular palsies and laryngeal nerve paralysis. Frequently, there appears to be a sequence in the development of neuromuscular side effects. Initially, one may encounter only sensory impairment and paraesthesiae. With continued treatment, neuritic pain may appear and later, motor difficulties. No reports have yet been made of any agent that can reverse the neuromuscular manifestations of vincristine sulphate. Convulsions, frequently with hypertension, have been reported in a few patients receiving vincristine. Several instances of convulsions followed by coma have been reported in children.Eye disorders: Transient cortical blindness and optic atrophy with blindness have been reported. Ear and labyrinth disorders: Treatment with vinca alkaloids has resulted rarely in both vestibular and auditory damage to the eighth cranial nerve. Manifestations include partial or total deafness, which may be temporary or permanent, and difficulties with balance, including dizziness, nystagmus and vertigo. Particular caution is warranted when vincristine sulphate is used in combination with other agents known to be ototoxic, such as the platinum-containing oncolytics.Cardiac disorders: Chemotherapy combinations which have included vincristine, when given to patients previously treated with mediastinal radiation, have been associated with coronary artery disease and myocardial infarction. Causality has not been established.Vascular disorders: Hypertension and hypotension have occurred.Respiratory disorders: Acute shortness of breath and severe bronchospasm have been reported following the administration of vinca alkaloids (see Section 4.5 Interaction with other medicinal products and other forms of interaction).Gastro-intestinal disorders: Constipation, abdominal cramps, paralytic ileus, diarrhoea, weight loss, nausea, vomiting, oral ulceration, intestinal necrosis and/or perforation, and anorexia have occurred. The constipation which may be encountered responds well to such usual measures as enemas and laxatives. Constipation may take the form of upper colon impaction and the rectum may be found to be empty on physical examination. Colicky abdominal pain, coupled with an empty rectum, may mislead the clinician. A flat film of the abdomen is useful in demonstrating this condition. A routine prophylactic regimen against constipation is recommended for all patients receiving vincristine sulphate. Paralytic ileus may occur, particularly in young children. The ileus will reverse itself upon temporary discontinuance of vincristine and with symptomatic care.Skin and subcutaneous tissue disorders: Alopecia, rash.Musculoskeletal, connective tissue and bone disorders: Muscle wasting, jaw pain, pharyngeal pain, parotid gland pain, bone pain, back pain, limb pain and myalgias have been reported; pain in these areas may be severe. Renal and urinary disorders: Polyuria, dysuria and urinary retention due to bladder atony have occurred. Other drugs known to cause urinary retention (particularly in the elderly) should, if possible, be discontinued for the first few days following administration of vincristine.General disorders: Rare cases of allergic-type reactions, such as anaphylaxis, rash and oedema, temporally related to vincristine therapy have been reported in patients receiving vincristine as a part of multi-drug chemotherapy regimens.Other: Fever, headache, injection site reaction (see Section 4.2 Posology and method of administration). | |