Introduction
A nitrogen mustard alkylating agent used as antineoplastic agent for the treatment of various malignant and nonmalignant diseases. Although it is less toxic than most other nitrogen mustards, it has been listed as a known carcinogen in the Fourth Annual Report on Carcinogens (NTP 85-002, 1985). (Merck Index, 11th ed)
Uses
Chlorambucil is a chemotherapy agent used in the management of chronic lymphocytic leukemia and malignant lymphomas.
For treatment of chronic lymphatic (lymphocytic) leukemia, childhood minimal-change nephrotic syndrome, and malignant lymphomas including lymphosarcoma, giant follicular lymphoma, Hodgkin's disease, non-Hodgkin's lymphomas, and Waldenström’s Macroglobulinemia.
Associated Conditions
Pharmacodynamics
Chlorambucil is an antineoplastic in the class of alkylating agents that is used to treat various forms of cancer. Alkylating agents are so named because of their ability to add alkyl groups to many electronegative groups under conditions present in cells. They stop tumor growth by cross-linking guanine bases in DNA double-helix strands - directly attacking DNA. This makes the strands unable to uncoil and separate. As this is necessary in DNA replication, the cells can no longer divide. In addition, these drugs add methyl or other alkyl groups onto molecules where they do not belong which in turn inhibits their correct utilization by base pairing and causes a miscoding of DNA. Alkylating agents are cell cycle-nonspecific. Alkylating agents work by three different mechanisms all of which achieve the same end result - disruption of DNA function and cell death.
Mechanism of Action
Alkylating agents work by three different mechanisms: 1) attachment of alkyl groups to DNA bases, resulting in the DNA being fragmented by repair enzymes in their attempts to replace the alkylated bases, preventing DNA synthesis and RNA transcription from the affected DNA, 2) DNA damage via the formation of cross-links (bonds between atoms in the DNA) which prevents DNA from being separated for synthesis or transcription, and 3) the induction of mispairing of the nucleotides leading to mutations.
Protein Binding
99%
Route of Elimination
Chlorambucil is extensively metabolized in the liver primarily to phenylacetic acid mustard. The pharmacokinetic data suggests that oral chlorambucil undergoes rapid gastrointestinal absorption and plasma clearance and that it is almost completely metabolized, having extremely low urinary excretion.
Half Life
1.5 hours
Food Interactions
- Avoid echinacea. Echinacea should be used with caution, if at all, in patients receiving therapeutic immunosuppressants. Monitor for reduced efficacy of the immunosuppressant during concomitant use.
- Drink plenty of fluids.
- Take on an empty stomach. Co-administration with food decreases bioavailability.
Dosage
Non-Hodgkin's lymphoma: 100-200 mcg/kg/day for 4-8 wk. Maintenance: Reduced daily dosage of intermittent courses of treatment.
Chronic lymphocytic leukaemia: Initially, 150 mcg/kg/day until the total leukocyte count falls to 10,000 microliter. Treatment may be resumed 4 wk after at a dose of 100 mcg/kg/day.
Waldenstrom's macroglobulinaemia: Starting dose of 6-12 mg daily until leucopenia occurs followed by 2-8 mg daily.