Introduction
A complex of related glycopeptide antibiotics from Streptomyces verticillus consisting of bleomycin A2 and B2 (B2 CAS # 9060-10-0). It inhibits DNA metabolism and is used as an antineoplastic, especially for solid tumors. Bleomycin A2 is used as the representative structure for Bleomycin.
Uses
Bleomycin is a chemotherapy agent used to treat various malignancies, including head and neck malignancy, lymphoma, and testicular tumors, among others.
For palliative treatment in the management malignant neoplasm (trachea, bronchus, lung), squamous cell carcinoma, and lymphomas.
Associated Conditions
Pharmacodynamics
Bleomycin is an antibiotic which has been shown to have antitumor activity. Bleomycin selectively inhibits the synthesis of deoxyribonucleic acid (DNA). The guanine and cytosine content correlates with the degree of mitomycin-induced cross-linking. At high concentrations of the drug, cellular RNA and protein synthesis are also suppressed. Bleomycin has been shown in vitro to inhibit B cell, T cell, and macrophage proliferation and impair antigen presentation, as well as the secretion of interferon gamma, TNFa, and IL-2. The antibiotic antitumor drugs are cell cycle-nonspecific except for Bleomycin (which has major effects in G2 and M phases).
Mechanism of Action
Although the exact mechanism of action of bleomycin is unknown, available evidence would seem to indicate that the main mode of action is the inhibition of DNA synthesis with some evidence of lesser inhibition of RNA and protein synthesis. As evident in in vitro studies, the DNA-cleaving actions of bleomycin is dependent on oxygen and metal ions. It is believed that bleomycin chelates metal ions (primarily iron) producing a pseudoenzyme that reacts with oxygen to produce superoxide and hydroxide free radicals that cleave DNA.
Absorption
Systemic absorption is approximately 45%.
Protein Binding
1%
Route of Elimination
It was reported that patients with moderately severe renal failure excreted less than 20% of the dose in the urine.
Half Life
115 minutes
Toxicity
Excessive exposure may cause fever, chills, nausea, vomiting, mental, confusion, and wheezing. Bleomycin may cause irritation to eyes, skin and respiratory tract. It may also cause a darkening or thickening of the skin. It may cause an allergic reaction.
Food Interactions
No interactions found.
Dosage
Squamous cell carcinoma, non-Hodgkin’s lymphoma, testicular carcinoma: 0.25 to 0.50 units/kg (10 to 20 units/m2) given intravenously, intramuscularly, or subcutaneously weekly or twice weekly.
Hodgkin’s disease: 0.25 to 0.50 units/kg (10 to 20 units/m2) given intravenously, intramuscularly, or subcutaneously weekly or twice weekly. After a 50% response, a maintenance dose of 1 unit daily or 5 units weekly intravenously or intramuscularly should be given.
Pulmonary toxicity of Bleomycin sulfat appears to be dose-related with a striking increase when the total dose is over 400 units. Total doses over 400 units should be given with great caution.
Note: When Bleomycin sulfat is used in combination with other antineoplastic agents, pulmonary toxicities may occur at lower doses.
Improvement of Hodgkin’s disease and testicular tumors is prompt and noted within 2 weeks. If no improvement is seen by this time, improvement is unlikely. Squamous cell cancers respond more slowly, sometimes requiring as long as 3 weeks before any improvement is noted.
Malignant Pleural Effusion: 60 units administered as a single dose bolus intrapleural injection
