-Jackie & Tim
The main use of cyclophosphamide is together with other chemotherapy agents in the treatment of lymphomas, some forms of leukemia[3] and some solid tumors.[4] It is a chemotherapy drug that works by slowing or stopping cell growth.
Cyclophosphamide also decreases the immune system's response to various diseases and conditions. Therefore, it has been used in various non-neoplastic autoimmune diseases where disease-modifying antirheumatic drugs (DMARDs) have been ineffective. For example, systemic lupus erythematosus (SLE) with severe lupus nephritis[5] may respond to pulsed cyclophosphamide (in 2005, however, standard treatment for lupus nephritis changed to mycophenolic acid (MMF) from cyclophosphamide). Cyclophosphamide is also used to treat minimal change disease,[6] severe rheumatoid arthritis,[7] Wegener's granulomatosis[8] (with trade name Cytoxan), and multiple sclerosis[9] (with trade name Revimmune).
A 2004 study[10] showed that the biological actions of cyclophosphamide are dose-dependent. At higher doses, it is associated with increased cytotoxicity and immunosuppression, while at low continuous dosage it shows immunostimulatory and antiangiogenic properties. A 2009 study of 17 patients with docetaxel-resistant metastatic hormone refractory prostate cancer showed a Prostate-specific antigen (PSA) decrease in 9 of the 17 patients. Median survival was 24 months for the entire group, and 60 months for those with a PSA response. The study concluded that low-dose cyclophosphamide "might be a viable alternative" treatment for docetaxel-resistant MHRPC and "is an interesting candidate for combination therapies, e.g., immunotherapy, tyrosine kinase inhibitors, and antiangiogenisis
Many people taking cyclophosphamide do have serious side effects. Side-effects include chemotherapy-induced nausea and vomiting (CINV), bone marrow suppression, stomach ache, diarrhea, darkening of the skin/nails, alopecia (hair loss) or thinning of hair, changes in color and texture of the hair, and lethargy. Hemorrhagic cystitis is a frequent complication, but this is prevented by adequate fluid intake and Mesna (sodium 2-mercaptoethane sulfonate). Mesna is a sulfhydryl donor and binds acrolein.
Cyclophosphamide is itself carcinogenic, potentially causing transitional cell carcinoma of the bladder as a long-term complication. It can lower the body's ability to fight an infection. It can cause temporary or (rarely) permanent sterility. A serious potential side-effect is Acute Myeloid Leukemia, referred to as secondary AML, due to it occurring secondarily to the primary disease being treated. The risk may be dependent on dose and a number of other factors, including the condition being treated, other agents or treatment modalities used (including radiotherapy), treatment intensity and length of treatment. For some regimens it is a very rare occurrence. For instance, CMF-therapy for breast cancer (where the cumulative dose is typically less than 20 grams of cyclophosphamide) seems to carry an AML risk of less than 1/2000th, with some studies even finding no increased risk compared to the background population. Other treatment regimens involving higher doses may carry risks of 1-2% or higher, depending on regimen. Cyclophosphamide-induced AML, when it happens, typically presents some years after treatment, with incidence peaking around 3–9 years. After 9 years, the risk has fallen to the level of the regular population. When AML occurs, it is often preceded by a Myelodysplastic syndrome phase, before developing into overt acute leukemia. Cyclophosphamide-induced leukemia will often involve complex cytogenetics, which carries a worse prognosis than de novo AML.
Other (serious) side effects include:
- gross and microscopic hematuria,
- unusual decrease in the amount of urine,
- mouth sores,
- unusual tiredness or weakness,
- joint pain,
- easy bruising/bleeding,
- existing wounds that are slow healing.
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