Cyclophosphamide
Cyclophosphamide is dissolved in 1 litre saline and given over one hour.
If the patient's actual body weight is >30% above the lean body weight then some dose reduction is usually recommended. Take the mid-point between these two weights and use this adjusted body weight for per kg dosage or for BSA calculations.
- During the days of cyclophosphamide treatment the antiemetics of choice are ondansetron and dexamethasone (8 mg IV q12h for adults). It should precede the first dose of cyclophosphamide and be continued until 24 hours after the final dose. You may also consider supplementing with metoclopramide if required.
- Allopurinol is given to prevent urate nephropathy at a dose of 300 mg PO daily (adult dose). It is commenced on admission and continued until day -2 (inclusive). If vomited, it should be re-administered.
- Fluid retention and electrolyte imbalances are common during the 2 days of cyclophosphamide treatment. Cyclophosphamide itself has an antidiuretic effect. The patient must be weighed and have serum electrolytes checked at least twice daily during these 2 days. Extra doses of frusemide are usually sufficient to treat fluid retention.
Adverse Effects
Adverse effects include: nausea and vomiting, diarrhoea, mucositis, haemorrhagic cystitis, reversible alopecia, sterility, cardiomyopathy, skin rash, fluid retention, hyponatraemia and facial discomfort.
- The antiemetics of choice are ondansetron (8 mg PO/IV q12h for adults) and dexamethasone 8 mg daily BD. It should precede the first dose of cyclophosphamide and be continued until the completion of TBI on day 0. Ondansetron should still be given if TBI precedes chemical conditioning. If nausea persists add metoclopramide 10-20 mg PO/IV 6 hourly and if required lorazepam 1-2 mg PO PRN.
Topic Code: 27317
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