Key Terms: Body surface area, Mucositis, Myelosuppression.
Definition
Mitoxantrone, also known by its trade name Novantrone, is an anticancer agent effective against certain kinds of leukemias. It is also used in Multiple Sclerosis (MS), and was approved by the Federal Drug Administration in 1987.
Purpose
Mitoxantrone is used with other drugs to treat acute non-lymphocytic leukemia (ANLL), a category that includes myelogenous, promyelocytic, monocytic and erythroid acute leukemia. In adults, ANLL accounts for up to 85% of all adult leukemia cases. Mitoxantrone may also be used in the treatment of acute lymphocytic leukemia, chronic myelocytic leukemia, ovarian cancer, advanced or recurrent breast cancer, prostate cancer, and MS.
Description
Mitoxantrone is classified as an anthracycline antitumor antibiotic, and closely resembles another drug in this category, daunorubicin. Although its precise mechanism is not clear, mitoxantrone is cell cycle non-specific, meaning that it is toxic to cells that are dividing, as well as those that are not.
Recommended Dosage
Mitoxantrone is given intravenously over a thirty-minute time period. Chemotherapy dosages are based on a person's body surface area (BSA), which is calculated in square meters using height and weight measurements. Drug dosages are ordered in milligrams per square meter (mg/m2).
In patients with cancer, the recommended dosage for induction therapy is 12mg/mg/m2 administered on the first three days of treatment. After that time, another chemotherapy drug is usually infused. This course of treatment is often adequate to induce remission, but may be repeated if it does not. In the second induction course, the dosage remains the same, but mitoxantrone is given for two days, rather than three, followed by other chemotherapy agents. Dosages may be altered, depending on the level of bone marrow toxicity the patient develops.
For patients with solid tumors, such as advanced hormone-refractory prostate cancer, a single dose of 12mg/mg/m2 is administered, and repeated every three to four weeks. Recent studies show that mitoxantrone used with glucocorticoids has resulted in improved pain control and quality of life in men with prostate cancer.
Precautions
Mitoxantrone's use in children has not been studied sufficiently to determine whether its use is safe and effective. It should not be used in individuals who have experienced a previous reaction to it.
Mitoxantrone is excreted by the liver and kidneys. It may alter the appearance of urine, causing it to be a blue-green color for approximately 24 hours. The sclera, or whites of the eyes, may temporarily be blue-tinged. Patients should not be alarmed by this change, but should alert their doctors if it is prolonged or is accompanied by other symptoms.
Mitoxantrone should not be administered to pregnant women, as damage to the fetus may occur. Throughout treatment, women should use methods to prevent pregnancy. It is excreted in breast-milk, so breast-feeding should be avoided during treatment.
Side Effects
Mitoxantrone can cause severe and sometimes rapid myelosuppression leading to decreased white blood cell, red blood cell, and platelet counts. Blood counts should be monitored frequently throughout treatment. The white blood cells tend to nadir, or drop to their lowest point, within ten to fourteen days after mitoxantrone is administered. Patients should also be examined for symptoms of low white blood cell count, which typically resemble those of an infection: sore throat, burning with urination, increased temperature, or swelling. Patients should also be carefully monitored for indications that platelet count is low. Symptoms may include unexplained bruises, bleeding or increased bleeding with menstruation, and headache.
Mitoxantrone can damage the heart, possibly causing changes that lead to congestive heart failure (CHF). Patients especially at risk are those previously treated with anthracyclines or radiation to the chest area, or those with an already existing heart condition. Symptoms to watch for include swelling of the hands and ankles, difficulty breathing, or heart palpitations.
Mitoxantrone can cause a severe, painful inflammation of the mucous membranes called mucositis. The condition may develop within a week of treatment. A patient may experience a burning sensation in his or her throat, as well as mouth pain. Mucositis typically resolves in a few weeks on its own, but there are measures one can take to hasten the process and provide comfort during healing. Hydration is very important to keep the mouth moist. Good oral hygiene is important—the teeth should be brushed with a very soft toothbrush, and flossed gently with unwaxed dental floss. (If bleeding occurs, using a toothbrush may not be safe. Patients should talk to their health care providers should this occur.) Your doctor or nurse may recommend a special mouthwash that helps relieve pain.
Patients undergoing treatment with mitoxantrone may be at risk for tumor lysis syndrome, a potentially life-threatening condition that develops when large numbers of cells rupture and release their contents into the blood stream. Preventative measures should be implemented to prevent adverse effects.
Interactions
Because mitoxantrone can alter normal blood counts, medications that contain aspirin should be avoided. Aspirin acts as a blood-thinner, and can predispose a person to bleeding. Patients should discuss all medications, whether they are prescribed or over-thecounter drugs, with their doctor to ensure there are no potential interactions. Cytarabine, another drug used to treat cancer, may increase the toxicity of mitixantrone if the drugs are used together.
—Tamara Brown, R.N.
