Pentostatin

Definition

Pentostatin is an anticancer (antineoplastic) agent belonging to the class of drugs called antimetabolites (compounds that prevent the synthesis and utilization of normal cellular metabolite). It is a natural product isolated from Streptomyces antibioticus. It also acts as a suppressor of the immune system. It is available under the brand name Nipent. Other common names for pentostatin include 2'-deoxycoformycin and 2'DCF.

Purpose

Pentostatin is primarily used to treat a particular type of cancer of the blood called hairy cell leukemia. It is also used in the treatment of low-grade lymphomas. Clinical trials are underway to determine the effectiveness of pentostatin in fighting cutaneous T-cell lymphoma (CTCL), chronic lymphocytic leukemia (CLL), non-Hodgkin's lymphomas (NHL), and prolymphocytic leukemia.

Description

Pentostatin chemically interferes with the synthesis of genetic material (DNA and RNA) of cancer cells, which prevents these cells from being able to reproduce and continue the growth of the cancer.

Recommended dosage

Pentostatin may be taken only as an injection. It is generally given once every two weeks. A typical dosage is four mg per square meter of body surface area. However, the dosage prescribed can vary widely depending on the patient, the cancer being treated, and whether or not other medications are also being taken.

Precautions

Pentostatin should be taken on an empty stomach. If stomach irritation occurs, it should be taken with small amounts of food or milk. Pentostatin should always be taken with plenty of fluids.

Pentostatin can cause an allergic reaction in some people. Patients with a prior allergic reaction to pentostatin should not take pentostatin.

Pentostatin can cause serious birth defects if either the man or the woman is taking this drug at the time of conception or if the woman is taking this drug during pregnancy.

Because pentostatin is easily passed from mother to child through breast milk, breast feeding is not recommended while pentostatin is being taken.

Pentostatin suppresses the immune system and interferes with the normal functioning of certain organs and tissues. For these reasons, it is important that the prescribing physician is aware of any of the following preexisting medical conditions:

• a current case of, or recent exposure to, chicken pox
• herpes zoster (shingles)
• a current case, or history of, gout or kidney stones
• all current infections
• kidney disease
• liver disease

Also, because pentostatin is such a potent immunosuppressant, patients taking this drug must exercise extreme caution to avoid contracting any new infections. They should do their best to:

• avoid any person with any type of infection
• avoid bleeding injuries, including those caused by brushing or flossing the teeth
• avoid contact of the hands with the eyes or nasal passages (inside of the nose) unless the hands have just been washed and have not touched anything else since this washing
• avoid contact sports or any other activity that could cause a bruising or bleeding injury

Side effects

The most common side effects of pentostatin are: cough, extreme fatigue, increased susceptibility to infection, loss of appetite (anorexia), skin rash or itching, nausea, temporary hair loss (alopecia), vomiting, and weight loss.

Less common side effects include: anxiety or nervousness, changes in vision, nosebleed, sores in the mouth or on lips, sore, red eyes, trouble sleeping (insomnia), numbness or tingling in the hands and/or feet, and swelling in the feet or lower legs.

A doctor should be consulted immediately if the patient experiences shortness of breath, chest or abdominal pain, persistent cough, fever and chills, pain in the lower back or sides, painful or difficult urination, unusual bleeding or bruising, blood in the urine or stool, or tiny red dots on the skin.

Interactions

Pentostatin should not be taken in combination with any prescription drug, over-the-counter drug, or herbal remedy without prior consultation with a physician. It is particularly important that the prescribing physician be aware of the use of any of the following drugs or any radiation therapy or chemotherapy medicine:

• amphotericin B
• antithyroid agents
• azathioprine
• chloramphenicol
• colchicine
• flucytosine
• fludarabine
• ganciclovir
• interferons
• plicamycin
• probenecid
• sulfinpyrazone
• vidarabine
• zidovudine

Paul A. Johnson, Ed.M.

Antineoplastic

—A drug that prevents the growth of a neoplasm by interfering with the maturation or proliferation of the cells of the neoplasm.

Hairy cell leukemia

—A rare form of cancer in which hairy cells grow out of control in the blood, liver, and spleen.

Lymphoma

—A malignant tumor of the lymphatic system.

Neoplasm

—New abnormal growth of tissue.