Mitomycin: What to Expect, Side Effects, and More

Mitomycin (brand name: Mutamycin) is an antibiotic sometimes used as a chemotherapy to treat advanced breast cancer.

Mitomycin is typically given in combination with other cancer drugs, including chemotherapy, as well as radiation.

Mitomycin damages DNA in cancer cells and other rapidly dividing cells, slowing or stopping their growth. 

Mitomycin is given intravenously. The usual dosage is 20 mg at six- to eight-week intervals.

Like almost all breast cancer medicines, mitomycin can cause side effects, some of them severe.

The most common side effects of mitomycin are:

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  low white blood cell counts

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  low red blood cell counts(anemia)

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  susceptibility to infection

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  fatigue

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  nausea

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  vomiting

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  hair loss

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  mouth sores

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  skin changes

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  hand-foot syndrome

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  irregular periods — this can include temporary cessation (usually resume after medication is completed) or permanent cessation of menstrual periods depending on your age and other factors

Some more serious side effects mitomycin may cause include:

Allergic reaction: if you experience pain, itching, redness, swelling, blisters, or sores, especially at the injection site, you may be allergic to Mitomycin. 

Lung problems: Tell your doctor if you’re experiencing wheezing, shortness of breath, or a persistent cough.

Kidney problems, specifically haemolytic-uraemic syndrome (HUS): symptoms include vomiting, bloody diarrhea, stomach pain, fever, chills, and headache.

Heart problems: Notify your healthcare provider if you have sudden weight gain or you notice swelling in your ankles or legs. If you feel lightheaded or dizzy, develop chest pain or pressure, pain in the left arm, back, or jaw, sweating, or shortness of breath, call 911 or go to the nearest emergency room.

Low platelet count (thrombocytopenia): Contact your doctor if you have any excessive bruising or bleeding — including nose bleeds, bleeding gums, or blood in your urine or stool.

Bone marrow suppression: Talk to your doctor about the signs and symptoms to look for, which vary widely and may resemble symptoms of other conditions. 

Exposure to this medication could cause birth defects, so you should not take this drug while pregnant. Talk to your doctor about whether this drug is right for you while breastfeeding. 

The cost of mitomycin may vary. The price you’ll pay depends on the drug manufacturer, your health insurance provider and plan, where you live, and the pharmacy you use. You may also be charged for the office visits required for mitomycin infusions.

Note: Your insurance company may require you to get prior authorization before covering mitomycin. 

Learn more about financial assistance and medicine cost-lowering tips.