indication

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.

pharmacology

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.

half life

1.5 hours

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.

drug interactions

Leflunomide: Immunosuppressants such as chlorambucil may enhance the adverse/toxic effect of leflunomide. Specifically, the risk for hematologic toxicity such as pancytopenia, agranulocytosis, and/or thrombocytopenia may be increased. Consider eliminating the use of a leflunomide loading dose in patients who are receiving other immunosuppressants in order to reduce the risk for serious adverse events such as hematologic toxicity. Also, patients receiving both leflunomide and another immunosuppressive medication should be monitored for bone marrow suppression at least monthly throughout the duration of concurrent therapy.

Natalizumab: Immunosuppressants such as chlorambucil may enhance the adverse/toxic effect of natalizumab. Specifically, the risk of concurrent infection may be increased. Patients receiving natalizumab should not use concurrent immunosuppressants.

Pimecrolimus: Pimecrolimus may enhance the adverse/toxic effect of immunosuppressants such as chlorambucil. Avoid use of pimecrolimus cream in patients receiving immunosuppressants.

Tacrolimus: Tacrolimus (Topical) may enhance the adverse/toxic effect of immunosuppressants sucb as chlorambucil. Avoid use of tacrolimus ointment in patients receiving immunosuppressants.

Trastuzumab: Trastuzumab may increase the risk of neutropenia and anemia. Monitor closely for signs and symptoms of adverse events.