Melphalan Health Dictionary

Alkylating agents are so named because they alkylate or chemically react with certain biochemical entities, particularly those concerned with the synthesis of NUCLEIC ACID. Alkylation is the substitution of an organic grouping in place of another grouping in a molecule.

Alkylating agents are important because they interfere with the growth and reproduction of cells, disrupting their replication. This CYTOTOXIC property is used to retard the division and growth of cancer cells, and alkylating drugs are widely used in the chemotherapy of malignant tumours – often in conjunction with surgery and sometimes with radiotherapy. Unfortunately, troublesome side-effects occur, such as: damage to veins when the drug is given intravenously, with resultant leakage into adjacent tissues; impaired kidney function due to the formation of URIC ACID crystals; nausea and vomiting; ALOPECIA (hair loss); suppression of BONE MARROW activity (production of blood cells); and adverse effects on reproductive function, including TERATOGENESIS. Indeed, cytotoxic drugs must not be given in pregnancy, especially during the ?rst three months. Prolonged use of alkylating drugs, especially when accompanying radiotherapy, is also associated with a sign?cant rise in the incidence of acute non-lymphocytic LEUKAEMIA. Among the dozen or so alkylating drugs in use are CYCLOPHOSPHAMIDE, CHLORAMBUCIL, MELPHALAN, BUSULFAN and THIOTEPA. (See also CHEMOTHERAPY.)... alkylating agents

A MALIGNANT disorder of PLASMA cells, derived from B-lymphocytes (see LYMPHOCYTE). In most patients the BONE MARROW is heavily in?ltrated with atypical, monoclonal plasma cells, which gradually replace the normal cell lines, inducing ANAEMIA, LEUCOPENIA, and THROMBOCYTOPENIA. Bone absorption occurs, producing di?use osteoporosis (see under BONE, DISORDERS OF). In some cases only part of the immunoglobulin molecule is produced by the tumour cells, appearing in the urine as Bence Jones PROTEINURIA.

The disease is rare under the age of 30, frequency increasing with age to peak between 60 and 70 years. There may be a long preclinical phase, sometimes as long as 25 years. When symptoms do occur, they tend to re?ect bone involvement, reduced immune function, renal failure, anaemia or hyperviscosity of the blood. Vertebral collapse is common, with nerve root pressure and reduced stature. The disease is eventually fatal, infection being a common cause of death. Local skeletal problems should be treated with RADIOTHERAPY, and the general disease with CHEMOTHERAPY

– chie?y the ALKYLATING AGENTS melphalan or cyclophosphamide. Red-blood-cell TRANSFUSION is usually required, together with plasmapheresis (see PLASMA EXCHANGE), and orthopaedic surgery may be necessary following fractures.... myelomatosis

The nitrogen analogues of mustard gas are among the most important ALKYLATING AGENTS used in the treatment of various forms of malignant disease. They include chlormethine, busulphan, chlorambucil and melphalan.... nitrogen mustards

any drug that damages or destroys cells: usually refers to those drugs used to treat various types of cancer. There are various classes of cytotoxic drugs, including *alkylating agents (e.g. *chlorambucil, *cyclophosphamide, *melphalan), *antimetabolites (e.g. *fluorouracil, *methotrexate, *mercaptopurine), *anthracycline antibiotics (e.g. *doxorubicin, *daunorubicin, *dactinomycin), *vinca alkaloids, and platinum compounds (e.g. *carboplatin, *cisplatin). Other cytotoxic drugs include *taxanes and *topoisomerase inhibitors, and some *monoclonal antibodies (e.g. *bevacizumab, *trastuzumab) have cytotoxic activity. All these drugs offer successful treatment in some conditions and help reduce symptoms and prolong life in others. Cytotoxic drugs destroy cancer cells by interfering with cell division, but they also affect normal cells, particularly in bone marrow (causing *myelosuppression), hair follicles (causing hair loss), the stomach lining (resulting in severe nausea and vomiting), mouth (causing soreness), and fetal tissue (they should not be taken during the later stages of pregnancy). Dosage must therefore be carefully controlled. See also chemotherapy.... cytotoxic drug

(multiple myeloma, myelomatosis) n. a malignant disease of the bone marrow, characterized by two or more of the following criteria: (1) the presence of an excess of abnormal malignant plasma cells in the bone marrow; (2) typical *lytic deposits in the bones on X-ray, giving the appearance of holes; (3) the presence in the serum of an abnormal gammaglobulin, usually IgG (an immunoglobulin; see paraprotein). *Bence-Jones protein may also be found in the serum or urine. The patient may complain of tiredness due to anaemia and of bone pain and may develop pathological fractures. Treatment is usually with such drugs as steroids, melphalan, cyclophosphamide, or thalidomide with local radiotherapy to particular areas of pain. See also plasmacytoma.... myeloma