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Cyclophosphamide
(Cytoxan)
Available: 25 mg and
50 mg tablets, and by intravenous infusion
Dose: Up to 2 mg/kg
orally; typically dosed 0.5-1.5 grams/m2
intravenously every 3-4 weeks
Cost: 50 mg tablets,
#30 = $125.99
Indications:
Treating serious complications of lupus, vasculitis,
scleroderma, or myositis
Side effects:
Nausea, vomiting, abdominal pain,
reversible thinning of the hair, and mouth sores are some of
the more common side effects patients may experience.
Suppression of the bone marrow leading to low blood counts is
also frequently encountered and can be used to adjust future
dosing of this medication. Many physicians actually desire to
slightly reduce the white blood cell count to around 3-4
thousand to ensure that the drug is achieving its desired
effect. Because cyclophosphamide irritates the bladder, it
may uncommonly cause bleeding along the surface of the
bladder, which in its most severe form is referred to as
hemorrhagic cystitis. This complication actually occurs
less frequently with intermittent intravenous dosing of
cyclophosphamide. While there is also an increased risk of
bladder cancer with prolonged use of cyclophosphamide, there
also appears to be an increased risk of other cancers, the
magnitude of which is undefined. Rarely, scarring in the lung
has been reported with prolonged use of this medication.
Monitoring:
Baseline blood count, urine test, kidney
and liver function is recommended. Thereafter, a blood count
every 2-4 weeks, and kidney and liver and kidney function
periodically at the discretion of the provider is prudent.
Urine tests should be performed every several months to look
for small amounts of blood, and annual urine cytology (a test
to screen for cancer cells) may be ordered at the discretion
of the provider. Continued presence of abnormalities in the
urine may prompt referral to a urologist.
Important points to
know: Patients should drink fluids
(up to 3 liters per day) to avoid bladder complications. The
oral form should be taken with food to minimize nausea. Cold
foods, such as ice cream, may be especially helpful in
improving tolerance of this medication. Report any persistent
vomiting to your health care provider. Do not take this
medication at bedtime, as this can increase contact of the
drug with the lining of the bladder. Promptly report any
excess bleeding or bruising to your provider. Because this
medication may make patients more susceptible to infections,
they should have up to date flu and pneumonia (Pneumovax)
vaccinations. Do not take this medication if you are pregnant
or breast feeding. Women should practice adequate
contraception while taking this drug and for several months
after discontinuing. Fertility may be impaired for both males
and females with long-term use.
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