CTX
Meaning of CTX: A three-letter shorthand for cyclophosphamide, a drug that arrives inactive and has to be switched on by the liver.
Definition of CTX
CTX is a common abbreviation for cyclophosphamide, a chemotherapy drug that cross-links the two strands of DNA so a cell cannot separate them to divide. It is given by mouth or by vein and is inactive as supplied, since liver enzymes have to convert it into the compound that does the damage. Besides cancer, it is used at lower doses in autoimmune disease.
Why does the liver have to activate it?
The molecule as manufactured is a shell built around an active core. Liver enzymes open it, and the fragments released travel in the blood and enter cells, where one of them binds DNA at two points and locks the strands together. A cell unable to pull its DNA apart cannot divide, and dividing cells are hit far harder than resting ones. That design was deliberate: the inactive form can be swallowed, and it does not destroy tissue at the injection site the way the older nitrogen mustards did.
What is it used for?
| Setting | Role |
|---|---|
| Lymphoma and leukemia | A backbone drug in several standard combinations |
| Breast cancer | Part of long-established combination regimens |
| Sarcoma and neuroblastoma | Used in children and young adults |
| Lupus and vasculitis | Lower doses, to suppress an attacking immune system |
| Relapsing nephrotic syndrome | A kidney disorder of children that keeps returning |
The immune uses rest on the same action seen from another angle, since the drug strikes rapidly dividing lymphocytes and an autoimmune attack depends on those cells multiplying. Doses there are a fraction of the cancer doses, and courses are usually limited in length because the long-term risks accumulate with total exposure.
What is the characteristic side effect?
One breakdown product, acrolein, leaves in the urine and irritates the bladder lining, which can cause bleeding into the bladder. Generous fluid intake dilutes it and a protective drug called mesna binds it in the urine, so the problem is largely preventable at high doses. Prolonged exposure carries a raised risk of bladder cancer years afterward. As with other members of this alkylating agent class, marrow suppression, hair loss, nausea and loss of fertility are expected effects.
Also known as
Used in a sentence
CTX was included in the regimen at a reduced dose because of impaired kidney function.
Good to know
CTX is not a unique abbreviation, since the same three letters stand for the bone turnover marker C-telopeptide, for the inherited disorder cerebrotendinous xanthomatosis and for the antibiotic ceftriaxone, so the surrounding context decides the meaning.