Key Terms: B cell, Clearance, Intravenous line, Kilogram, Lymphatic system, Milligram, Mutant.
Definition
Mycophenolate mofetil (brand name CellCept) is a drug that has been shown to inhibit tumor growth in rodents, and that may prove useful in treating tumors in humans.
Purpose
The Food and Drug Administration (FDA) approved the use of mycophenolate mofetil in August 2000 for use in patients undergoing liver transplants, and the drug is used primarily to ease the acceptance of a transplanted organ by a recipient. The drug makes acceptance of the transplanted organ more likely because it prevents the recipient from mounting an immune response to the organ, or treating it like a foreign invader. The drug also seems to have the ability to inhibit tumor growth, and may prove effective in treating certain kinds of cancer.
In laboratory studies, mycophenolate mofetil has inhibited tumor growth in cancers of the pancreas, colon, lung, and blood. The value of the drug for anticancer therapy is still being evaluated.
In addition to its use in treating cancer, mycophenolate mofetil has been used by dermatologists to treat pyoderma gangrenosum, a rare skin disorder of unknown origin characterized by ulcerated areas on the legs. Pyoderma gangrenosum is associated with systemic diseases in about half the patients diagnosed with it, and mycophenolate mofetil has been found to be effective in treating these patients either alone or in combination with prednisone.
Mycophenolate mofetil is reported to be effective in relieving pain in patients with cluster headache; however, this use of the drug is considered investigational as of 2004.
Description
Mycophenolate mofetil suppresses, or prevents activity of, cells in the lymphatic system, both T cells and B cells. Under normal circumstances, T cells mount an immune response by reacting directly with foreign materials in the body and B cells release compounds that attack foreign materials. But during a transplant, T cells and B cells can cause a reaction that leads to the rejection of a donor organ.
Recommended Dosage
The drug is given orally and by intravenous line. Dosages given for cancer therapy are experimental. To prevent immune response during organ transplants, the drug is dispensed in capsules of 250 mg, tablets of 500 mg, and by intravenous line in doses of 500 mg. Time intervals between dosages are determined according to the rate of the drug's breakdown in the patient's body.
Precautions
Mycophenolate mofetil is known to cause or may cause lymphomas and skin cancer. The benefit of taking the drug must be weighed against the increased risk of the cancers it causes.
It is critical for the patient's doctor to monitor blood levels carefully when using this drug, as patients vary widely in their rate of clearance of mycophenolate mofetil, particularly when it is given in combination with other immunosuppressants.
Side Effects
In addition to increasing the risk of lymphomas and skin cancer, mycophenolate mofetil may cause a number of other unwanted reactions. They include dizziness, headache, trembling, as well as pain in the chest, swelling (edema), and high blood pressure (hypertension). Many digestive tract upsets from constipation to diarrhea to vomiting are also possible side effects. There is also a chance of hemorrhage, or uncontrolled bleeding in the digestive tract.
Interactions
Taking the drug is likely to make oral contraceptives ineffective and another form of birth control should be used. Stomach medications that contain magnesium and aluminum hydroxides, such as antacids, can block the uptake of mycophenolate mofetil across the gut. They should be avoided. As always, the physician in charge of the care plan should be told of every drug a patient is taking so that the potential for interactions can be avoided. The drug is considered superior to some others used as a suppressant of the immune response in transplants because it does not show as many drug interactions as other drugs do. But the short list of interactions might be in part related to its limited time on the market, and interactions that are yet unidentified.
Resources
Books
Wilson, Billie A., Margaret T. Shannon, and Carolyn L. Stang. Nurses Drug Guide 2000. Stamford, CT: Appleton & Lange, 2000.
Periodicals
Fireman, M., A. F. DiMartini, S. C. Armstrong, and K. L. Cozza. "Immunosuppressants." Psychosomatics 45 (July-August 2004): 354–360.
Jackson, J. Mark, MD, and Jeffrey P. Callen, MD. "Pyoderma Gangrenosum." eMedicine August 4, 2003.
Lee, M. R., and A. J. Cooper. "Mycophenolate Mofetil in Pyoderma Gangrenosum." Journal of Dermatological Treatment 15 (September 2004): 303–307.
Rozen, T. D. "Complete But Transient Relief of Chronic Cluster Headache with Mycophenolate Mofetil." Headache 44 (September 2004): 818–820.
Shaw, L. M., A. Nawrocki, M. Korecka, et al. "Using Established Immunosuppressant Therapy Effectively: Lessons from the Measurement of Mycophenolic Acid Plasma Concentrations." Therapeutic Drug Monitoring 26 (August 2004): 347–351.
Organizations
American Society of Health-System Pharmacists (ASHP). 7272 Wisconsin Avenue, Bethesda, MD 20814. (301) 657-3000.
United States Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857-0001. (888) INFO-FDA.
—Diane M. Calabrese; Rebecca J. Frey, PhD
