What is mycophenolate mofetil (CellCept®)?
Mycophenolate mofetil is an immunosuppressive medication that reduces the activity of the body’s immune system. Medications that suppress the immune system are used in patients with myasthenia gravis (MG) because MG is an autoimmune disorder that results in production of abnormal antibodies directed against a patient’s own muscle tissue instead of a foreign entity (e.g. bacteria). Originally approved as a transplant anti-rejection drug, mycophenolate mofetil has been found to be helpful in autoimmune illnesses like MG.
How does mycophenolate mofetil work?
Under normal circumstances, the immune system produces proteins called antibodies that protect the body from infections (e.g. viruses and bacteria) and from abnormally growing cells (e.g. cancers). In autoimmune MG, the immune system becomes confused and produces abnormal antibodies directed against a patient’s own muscle tissue. The abnormal antibodies block or destroy important receptors on the muscle resulting in muscle weakness.
Mycophenolate mofetil reduces the production of lymphocytes, the white blood cells that produce antibodies. Reduction of the abnormal antibodies in MG allows muscle tissue to heal and function more normally. As muscle heals, patients experience an improvement in muscle strength.
How is mycophenolate mofetil used in the treatment of MG?
Mycophenolate mofetil may be used together with another immunosuppressant agent such as prednisone, or as the only immunosuppressive agent. In many MG patients, medications like mycophenolate mofetil are used to reduce the dose of corticosteroids (e.g. prednisone) or eliminate the need for corticosteroid therapy completely. It may take you 6 – 14 months to notice improvement from mycophenolate mofetil therapy. When mycophenolate mofetil treatment is successful, you should notice gradual improvement in muscle strength and reduced need for other MG medications during this time period. Once you have been on mycophenolate mofetil for an extended period (3 – 5 years) of stability with good muscle strength, you and your physician can discuss slowly reducing the dose.
What are some special considerations to discuss with your health care provider before starting mycophenolate mofetil?
Before prescribing mycophenolate mofetil, your MG physician will ask you if you have anemia or any blood conditions, unusual bleeding or bruising, or any viral or bacterial infections.
If you are a woman, your physician will want to know if you are pregnant, planning on getting pregnant, or breast feeding. First trimester pregnancy loss and congenital malformations have been reported with patients taking mycophenolate mofetil. Women who are planning a pregnancy or who become pregnant while taking mycophenolate mofetil should discuss potential risks and options with their physician. It is recommended that women of child bearing age use two forms of birth control simultaneously when treated with mycophenolate mofetil.
How should mycophenolate mofetil be taken?
Mycophenolate mofetil is an oral medication prescribed based on your body weight. Y Take mycophenolate mofetil exactly as prescribed by your MG physician. Swallow the tablet or capsule with water. Do not crush the tablet or open the capsule. If your skin comes in contact with the contents of the capsule or a broken tablet, rinse thoroughly with water. Be certain to take this medication exactly as prescribed at regular intervals. If you miss a dose of mycophenolate mofetil, take it as soon as you can. If it is almost time for the next dose, take only that dose. Never take extra medicine or double doses. A liquid version of mycophenolate mofetil is available if you cannot swallow the capsules or tablets.
Does mycophenolate mofetil interact with other medicines or vaccines?
Mycophenolate mofetil can interact with other drugs. For this reason, it is important to tell your physician about all other medicines that you are taking. Be certain to mention all over-the-counter drugs, nutritional supplements or any herbal products that you are using. Antacids, vaccines, cholestyramine (a cholesterol reducing drug) and drugs that suppress your immune system can interact with mycophenolate mofetil.
Administration of live vaccines is not recommended in patients treated with mycophenolate mofetil. Non-live vaccines (e.g. injectable influenza vaccine) may be administered in patients treated with mycophenolate mofetil.
What are the possible adverse effects of mycophenolate mofetil?
Your physician will carefully monitor your situation for potential adverse effects. People with MG take much smaller doses of mycophenolate mofetil than those using it to avoid transplant rejection. For this reason, common adverse effects are limited and mainly related to gastrointestinal problems including nausea and diarrhea, low white blood counts, anemia and skin rash.
Mycophenolate mofetil and other immunosuppressant agents may increase the risk of infections. The risk of infection is higher when and if you are treated with multiple simultaneous immunosuppressant medications. It is important to avoid individuals with infectious illnesses and to notify your physician if you develop persistent signs of infection. There is a minimally increased risk of cancer associated with mycophenolate mofetil usage.
How will a physician monitor a patient taking mycophenolate mofetil?
Appointments will be scheduled at regular intervals to monitor your progress. At these appointments, your physician will ask you a series of questions as well as perform physical examinations and laboratory tests that provide important information to evaluate the safety and effectiveness of mycophenolate mofetil in your case. To watch for anemia or a decrease in the white cell count, blood samples will typically be examined frequently during the first few months of this therapy and then less often.