Fluorouracil may be used alone, or in combination for its palliative action in the management of common malignancies particularly cancer of the colon and breast, either as a single agent or in combination with other cytotoxic agents.
Selection of an appropriate dose and treatment regime will depend upon the condition of the patient, the type of carcinoma being treated and whether Fluorouracil is to be administered alone or in combination with other therapy. Initial treatment should be given in hospital and the total daily dose should not exceed 1 gram. It is customary to calculate the dose in accordance with patient’s actual weight unless there is obesity, oedema or some other form of abnormal fluid retention such as ascites. In this case, ideal weight should be used as the basis for the calculation.
Fluorouracil injection can be given by intravenous injection or, intravenous or intra-arterial infusion.
Fluorouracil injection should not be mixed directly, in the same container, with other chemotherapeutic agents or intravenous additives.
Fluorouracil is often administered concomitantly with leucovorin which may potentiate the therapeutic effects of fluorouracil. Therefore, the toxicity of fluorouracil, especially GI and hematologic, may be increased. Careful monitoring should be observed and the dose of fluorouracil may be decreased based on current guidelines.
Adult Dose
The following regimen have been recommended for use as a single agent:
Initial Treatment: This may be in the form of an infusion or an injection, the former usually being preferred because of lesser toxicity.
Intravenous infusion: 15mg/kg bodyweight but not more than 1g per infusion, diluted in 500ml of 5% glucose or 0.9% NaCl injection and given by intravenous infusion at a rate of 40 drops per minute over 4 hours. Alternatively the daily dose may be infused over 30 – 60 minutes or may be given as a continuous infusion over 24 hours. The infusion may be repeated daily until there is evidence of toxicity or a total dose of 12 – 15g has been reached.
Intravenous Injection: 12mg/kg bodyweight, but not more than the recommended 1g daily dose may be given daily for 3 days and then, if there is no evidence of toxicity, 6mg/kg on alternate days for 3 further doses. An alternative regimen is 15mg/kg as a single intravenous injection once a week throughout the course.
Intra-arterial Infusion: 5/7.5mg/kg may be given by 24 hour continuous intra-arterial infusion.
Maintenance Therapy: An initial intensive course may be followed by maintenance therapy providing there are no significant toxic effects. In all instances, toxic side effects must disappear before maintenance therapy is started. If toxic symptoms appear during maintenance, therapy must be discontinued until the symptoms resolve.
The initial course of fluorouracil can be repeated after an interval of 4 to 6 weeks from the last dose or, alternatively, treatment can be continued with intravenous injections of 5-15mg/kg bodyweight at weekly intervals.
This sequence constitutes a course of therapy. Some patients have received up to 30g at a maximum rate of 1 g daily. A more recent alternative method is to give 15mg/kg IV once a week throughout the course of treatment. This obviates the need for an initial period of daily administration.
In combination with Irradiation: Irradiation combined with 5FU has been found to be useful in the treatment of certain types of metastatic lesions in the lungs and for the relief of pain caused by recurrent, inoperable growth. The standard dose of 5FU should be used.
