Zitomycin

Mitomycin is an antibiotic isolated from the broth of Streptomyces verticillus Yingtanensis which has been shown to have antimetabolic activity.

Mitomycin is a blue-violet crystalline powder with the molecular formula of C₁₅H₁₈N₄O₅ and a molecular weight of 334.33. Its chemical name is 7-amino-9α-methoxymitosane and it has the following structural formula:

Mitomycin is a sterile lyophiliized mixture of mitomycin and mannitol, which, when reconstituted with Sterile Water for Injection, provides a solution for application in glaucoma filtration surgery. Mitomycin is supplied in vials containing 0.2 mg of mitomycin. Each vial also contains mannitol 0.4 mg, at a 1:2 ratio of mitomycin to mannitol. Each mL of reconstituted solution contains 0.2 mg mitomycin and has a pH between 5.0 and 8.0.

Zitomycin is not recommended as single-agent, primary therapy. It has been shown to be useful in the therapy of disseminated adenocarcinoma of the stomach or pancreas in proven combinations with other approved chemotherapeutic agents and as palliative treatment when other modalities have failed. Zitomycin is not recommended to replace appropriate surgery and/or radiotherapy.

Usage:

As directed by the physicians.

Zitomycin selectively inhibits the synthesis of deoxyribonucleic acid (DNA). The guanine and cytosine content correlates with the degree of Zitomycin -induced cross-linking. At high concentrations of the drug, cellular RNA and protein synthesis are also suppressed.

In humans, Zitomycin is rapidly cleared from the serum after intravenous administration. Time required to reduce the serum concentration by 50% after a 30 mg bolus injection is 17 minutes. After injection of 30 mg, 20 mg, or 10 mg I.V., the maximal serum concentrations were 2.4 µg/mL, 1.7 µg/mL, and 0.52 µg/mL, respectively. Clearance is effected primarily by metabolism in the liver, but metabolism occurs in other tissues as well. The rate of clearance is inversely proportional to the maximal serum concentration because, it is thought, of saturation of the degradative pathways.

Approximately 10% of a dose of Zitomycin is excreted unchanged in the urine. Since metabolic pathways are saturated at relatively low doses, the percent of a dose excreted in urine increases with increasing dose. In children, excretion of intravenously administered Zitomycin  is similar.

• Read the label carefully before use

• Store between 15°C to 30°C. Protect from light.

• Keep out of the reach of children

Acute shortness of breath and severe bronchospasm have been reported following the administration of vinca alkaloids in patients who had previously or simultaneously received Zitomycin . The onset of this acute respiratory distress occurred within minutes to hours after the vinca alkaloid injection. The total number of doses for each drug has varied considerably. Bronchodilators, steroids and/or oxygen have produced symptomatic relief.

A few cases of adult respiratory distress syndrome have been reported in patients receiving Zitomycin in combination with other chemotherapy and maintained at FIO₂ concentrations greater than 50% perioperatively. Therefore, caution should be exercised using only enough oxygen to provide adequate arterial saturation since oxygen itself is toxic to the lungs. Careful attention should be paid to fluid balance and overhydration should be avoided.

Bladder fibrosis/contraction has been reported with intravesical administration (not an approved route of administration), which in rare cases has required cystectomy.

Nursing Mothers

It is not known if mitomycin is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from mitomycin, it is recommended that nursing be discontinued when receiving mitomycin therapy.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.