Antibiotic
antineoplastic drugs
Antibiotic antineoplastic drugs are antimicrobial products thatproduce tumoricidal
(tumor-destroying) effects by binding with DNA. These drugs inhibit the
cellular processes of normal and ma-lignant cells. They include:
anthracyclines (daunorubicin, doxorubicin,
idarubicin)
·
bleomycin
·
dactinomycin
·
mitomycin
·
mitoxantrone.
Antibiotic antineoplastic drugs are usually
administered I.V.
Some drugs are also administered directly into the
body cavity be-ing treated. Bleomycin, doxorubicin, and mitomycin are
some-times given as topical bladder instillations, resulting in minimal
systemic absorption. When bleomycin is injected into the pleural space for malignant
effusions, up to one-half of the dose is ab-sorbed systemically.
Distribution of antibiotic antineoplastic drugs
throughout the body varies; their metabolism and elimination also vary.
With the exception of mitomycin, antibiotic
antineoplastic drugs intercalate, or insert themselves, between adjacent base
pairs of a DNA molecule, physically separating them.
Remember, DNA looks like a twisted ladder with the
rungs made up of pairs of nitrogenous bases. These drugs insert themselves
between those nitrogenous bases. Then, when the DNA chain replicates, an extra
base is inserted opposite the intercalated an-tibiotic, resulting in a mutant
DNA molecule. The overall effect is cell death.
Mitomycin is activated inside the cell to a
bifunctional or even tri-functional alkylating drug. Mitomycin produces
single-strand breakage of DNA. It also cross-links DNA and inhibits DNA
syn-thesis.
Antibiotic antineoplastic drugs act against many
cancers, includ-ing:
·
acute leukemia
·
breast, ovarian, bladder, and lung cancer
·
cancers of the GI tract
·
choriocarcinoma
·
Ewing’s sarcoma (a malignant tumor that originates in bone marrow,
typically in long bones or the pelvis) and other soft-tissue sarcomas
·
Hodgkin’s disease and malignant lymphomas
·
melanoma
·
osteogenic sarcoma and rhabdomyosarcoma (malignant neo-plasm composed of
striated muscle cells)
·
squamous cell carcinoma of the head, neck, and cervix
·
testicular cancer
·
Wilms’ tumor (a malignant neoplasm of the kidney, occurring in young
children).
Antibiotic antineoplastic drugs interact with many
other drugs. (See Adverse reactions to
antibiotic antineoplastic drugs.)
§ Concurrent therapy with fludarabine and
idarubicin isn’t recom-mended because of the risk of fatal lung toxicity.
§ Bleomycin may decrease serum digoxin and
serum phenytoin levels.
§ Doxorubicin may reduce serum digoxin levels.
§ Combination chemotherapies enhance leukopenia
and thrombo-cytopenia (reduced number of platelets).
§ Mitomycin plus vinca alkaloids may cause
acute respiratory dis-tress.
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