BLEOMYCIN

 BLEOMYCIN

 BRAND NAME:- BLEOCIN, BELCAM injection 

BLEOMYCIN is a mixture of closely related glycopeptide antibiotics having potent antitumour activity. Used to treat various malignancies, including head and neck malignancy, lymphoma, and testicular tumors, among others.

PHARMACOLOGY:-

BLEOMYCIN is a glycopeptide antibiotics having antitumour activity. It chelates copper or iron , produces superoxide ions and intercalates between DNA strands —causes chain scission and inhibits repair. It is 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:-

Bleomycin, a non-heme iron protein,[17] acts by induction of DNA strand breaks.[18] Some studies suggest bleomycin also inhibits incorporation of thymidine into DNA strands. DNA cleavage by bleomycin depends on oxygen and metal ions, at least in vitro. The exact mechanism of DNA strand scission is unresolved, but it has been suggested that bleomycin chelates metal ions (primarily iron), producing a pseudoenzyme that reacts with oxygen to produce superoxide and hydroxide free radicals that cleave DNA. An alternative hypothesis states that bleomycin may bind at specific sites in the DNA strand and induce scission by abstracting the hydrogen atom from the base, resulting in strand cleavage as the base undergoes a Criegee-type rearrangement, or forms an alkali-labile lesion.[In addition, these complexes also mediate lipid peroxidation and oxidation of other cellular molecules. Therefore, bleomycin is used in combination with doxorubicin in Hodgkins lymphoma, as they have additive and complementary effects on the DNA, since doxorubicin acts by intercalating between DNA strands, and also acts on topoisomerase II enzyme thus relaxing the topoisomerase complexes. 

USED:-

used to treat various malignancies, including head and neck malignancy, lymphoma, and testicular tumors, among others. 

SIDE EFFECTS:-

The most common side effects are flu-like symptoms and include fever, rash, dermatographism, hyperpigmentation, alopecia (hair loss), chills, and Raynaud's phenomenon (discoloration of fingers and toes).  

DOSE:- 30mg twice weekly i .v. or i.m (total dose 300-400mg)