MITOMYCIN (PDH)
Mutamycin
· Pharmacologic classification: antineoplastic antibiotic (cell cycle-phase nonspecific)
· Therapeutic classification: antineoplastic
· Pregnancy risk category C
How supplied
Available by prescription only.
Injection: 5-mg, 40-mg vials
Indications, route and dosage
Dosage and indications may vary.
Stomach, pancreatic, breast, colon, head, neck, lung, and hepatic cancer.
Adults: 2 mg/m2 I.V. daily for 5 days. Stop drug for 2 days, then repeat dose for 5 more days; or 10 to 20 mg/m2 as a single dose. Repeat cycle q 6 to 8 weeks. Stop drug if WBC count is below 3,000/mm3 or platelet count is below 75,000/mm3.
Pharmacokinetics
· Absorption: Because of its vesicant nature, mitomycin must be administered intravenously.
· Excretion: Mitomycin and its metabolites are excreted in urine. A small portion is eliminated in bile and feces.
Contraindications and precautions
Mitomycin is contraindicated in patients with a history of hypersensitivity to the drug; in patients with a WBC count below 3,000/mm3, platelet count below 75,000/mm3, or serum creatinine level above 1,7 mg/100 ml; and in those with coagulation disorders, prolonged prothrombin time, or serious infections, because of the potential for adverse effects.
Interactions
Concomitant use with dextran and urokinase enhances the cytotoxic activity of mitomycin. Through a series of enzymatic processes, these agents increase autolysis of cells, adding to the cell death caused by mitomycin.
Effects on diagnostic tests
Mitomycin therapy, through drug-induced renal toxicity, may increase serum creatinine and BUN concentrations.
Adverse reactions
· CNS: paresthesias.
· GI: nausea, vomiting, anorexia, stomatitis.
· HEMA: bone marrow depression (dose-limiting), thrombocytopenia, leukopenia (may be delayed up to 8 weeks and may be cumulative with successive doses).
· Local: desquamation, induration, pruritus, pain at site of injection; with extravasation, cellulitis, ulceration, sloughing.
· Other: reversible alopecia; purple coloration of nail beds; fever; syndrome characterized by microangiopathic hemolytic anemia, thrombocytopenia, renal toxicity, and hypertension.
Note: Drug should be discontinued if WBC count is below 3,000/mm3 or platelet count is below 75,000/mm3.
Overdose and treatment
Clinical manifestations of overdose include myelosuppression, nausea, vomiting, and alopecia.
Treatment is usually supportive and includes transfusion of blood components, antiemetics and antibiotics for infections that may develop.
Special considerations
· To reconstitute 5-mg vial, use 10 ml of sterile water for injection; to reconstitute 20-mg vial, use 40 ml of sterile water for injection, to give a concentration of 0,5 mg/ml.
· Drug may be administered by I.V. push injection slowly over 5 to 10 minutes into the tubing of a freely flowing I.V. infusion.
· Drug can be further diluted to 100 to 150 ml with normal saline solution or dextrose 5% in water for I.V. infusion (over 30 to 60 minutes or longer).
· Reconstituted solution remains stable for 1 week at room temperature and for 2 weeks if refrigerated.
· Mitomycin has been used intraarterially to treat certain tumors, for example, into hepatic artery for colon cancer. It has also been given as a continuous daily infusion.
· An unlabeled use of this drug is to treat small bladder papillomas. It is instilled directly into the bladder in a concentration of 20 mg/20 ml sterile water.
· Ulcers caused by extravasation develop late and dorsal to the extravasation site. Apply cold compresses for at least 12 hours.
· Continue CBC and blood studies at least 7 weeks after therapy is stopped. Monitor for signs of bleeding.
Information for the patient
Tell the patient to avoid exposure to people with infections.
Warn the patient not to receive immunizations during therapy and for several weeks afterwards. Members of the same household should not receive immunizations during the same period.
Reassure the patient that hair should grow back after treatment has been discontinued.
Tell the patient to call promptly if he develops a sore throat or fever or notices any unusual bruising or bleeding.
Breast-feeding
It is not known whether mitomycin distributes into breast milk. However, because of the potential for serious adverse reactions, mutagenicity, and carcinogenicity in the infant, breast-feeding is not recommended.
