Antibiotic antineoplastic drugs
Antibiotic antineoplastic drugs
Antibiotic antineoplastic drugs are antimicrobial products that produce tumoricidal (tumor-destroying) effects by binding with DNA. These drugs inhibit the cellular processes of normal and malignant cells. They include:
- anthracyclines (daunorubicin, doxorubicin, idarubicin)
- bleomycin
- dactinomycin
- mitomycin
- mitoxantrone.
Pharmacokinetics
Antibiotic antineoplastic drugs are usually administered I.V.
Direct deliveries
Some drugs are also administered directly into the body cavity being treated. Bleomycin, doxorubicin, and mitomycin are sometimes 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 absorbed systemically.
Distribution, metabolism, and excretion
Distribution of antibiotic antineoplastic drugs throughout the body varies; their metabolism and elimination also vary.
Pharmacodynamics
With the exception of mitomycin, antibiotic antineoplastic drugs intercalate, or insert themselves, between adjacent base pairs of a DNA molecule, physically separating them.
Taking the extra base
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 antibiotic, resulting in a mutant DNA molecule. The overall effect is cell death.
Clean break
Mitomycin is activated inside the cell to a bifunctional or even trifunctional alkylating drug. Mitomycin produces single-strand breakage of DNA. It also cross-links DNA and inhibits DNA synthesis.
Warning!Adverse reactions to antibiotic antineoplastic drugs
The primary adverse reaction to antibiotic antineoplastic drugs is bone marrow suppression. Irreversible cardiomyopathy and acute electrocardiogram changes can also occur as well as nausea and vomiting.
Extra steps
An antihistamine and an antipyretic should be given before bleomycin to prevent fever and chills. Anaphylactic reactions can occur in patients receiving bleo-mycin for lymphoma, so test doses should be given first.
Seeing colors
Doxorubicin may color urine red; mitoxantrone may color it blue-green.
Pharmacotherapeutics
Antibiotic antineoplastic drugs act against many cancers, including:
- 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 neoplasm 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).
Drug interactions
Antibiotic antineoplastic drugs interact with many other drugs.
- Concurrent therapy with fludarabine and idarubicin isn’t recommended 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 thrombocytopenia (reduced number of platelets).
- Mitomycin plus vinca alkaloids may cause acute respiratory distress.
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