Many of the drugs used for myositis suppress the immune system. In myositis and other autoimmune diseases, the body makes antibodies that, instead of attacking outside germs as invaders, attack its own tissues. By suppressing the activity of the immune system to some extent, these drugs also help suppress myositis activity. However, immunosuppressant drugs also make you more susceptible to infections -- and less able to fight them. Therefore, if you develop any other symptoms - even cold symptoms - while taking these drugs, call your doctor right away.
Corticosteroids, often called steroids, are used to decrease inflammation in myositis. The most commonly prescribed type is prednisone; others include: cortisone, hydrocortisone, prednisone, prednisolone, methylprednisolone, triamcinolone, dexamethasone, and betamethasone. They are sold under many brand names. When used in high doses, they can suppress the immune system. Dosage of steroids varies depending on severity of the illness. Short term effects may include: weight gain, bloating, rash, acne, gastrointestinal (GI) problems, insomnia, hair loss, irritability, mood swings, headaches, and flushing of the skin. The long-term side effects may include: cataracts, steroid-induced diabetes, and bone problems, such as osteoporosis or avascular necrosis.
Patients on steroids should have annual or bi-annual eye exams for cataracts. You also should have a baseline bone density scan, called a DEXA scan, to determine your bone density. Then, you should have re-checks annually or as recommended by your physician. Avascular necrosis is when a part of the bone is not getting enough blood. As a result of this, it causes the bone to die and can cause a lot of pain. If you experience any new pain, be sure to tell your doctor.
Methylprednisolone (brand named Solumedrol) is a steroid medication that is given intravenously. It can be used to lower or maintain the oral dose of steroids. It is used to suppress flares or as a maintenance therapy. Dosage varies between 500 to 1000 mg. It can be given between one to three days per month or as needed. It can be administered on an outpatient or inpatient basis The procedure runs between one to three hours, depending on the practitioner and the facility. However, medical staff should always be present when patients are receiving this treatment. Some patients who are on Solumedrol do not take oral steroids. Patients may also feel like they have gained a few pounds after the therapy. This is a result of the body retaining water. So be careful about salt intake: the more salt you consume while taking this medication, the more water you will retain. The water retention subsides within a few days through urination.
Azathioprine (brand named Imuran)Azathioprine is an immunosuppressant that can be used alone or in conjunction with other medications. Dosage varies from 50 to 150 mg a day, and it is given orally (by pill). It can be given once or in divided doses. Side effects may include hair loss, low blood counts, elevation in liver enzymes, GI problems (i.e nausea, vomiting), and secondary infections. Because this medication can suppress white and red blood cells, you should have blood tests at least once a month. If the blood cells are too low, it can create health problems.
Methotrexate (brand named Rheumatrex)This medication, also an immunosuppressant, is similar to azathioprine. It can be used alone or in conjunction with additional medications to suppress the immune system enough to control disease activity. Dosage varies between 2.5 to 25mg per week, and it can be given orally or by intramuscular injection. Side effects are similar to those with azathioprine.
Immune Gamma Globulin (IGG)This is an immune serum which is derived from large pools of human plasma. It has been in use for more than 15 years to treat many different diseases and, more recently, to treat myositis. However, it is expensive because of the work involved in its preparation. The FDA issues strict guidelines that involve many screenings for potential viruses.
Gamma globulin is used to lower a myositis patient's CPK level. The dosage is based on a patient's weight and is given intravenously over three to four days. The length of the procedure depends on the amount of IGG given in a day and the rate at which the medication is tolerated. Reactions related to the rate at which the infusion is given involve fever, chills and/or chest tightness. If you experience any of these rate-related reactions, notify the medical staff immediately. Once the medication rate is lowered or the infusion stopped, the reaction will resolve.
The side effects of gamma globulin may include mild to severe headaches. Within 48 hours, this medication peaks in the cerebrospinal fluid, which can cause inflammation of the meninges. This is called aseptic meningitis. Aseptic means it is not viral or bacterial. Meningitis means inflammation of the meninges -- the layers that cover the brain and the spinal cord. This may require you to stay in bed for a few days and take painkillers following the treatment, but there are no known long-term side effects. Other side effects include fatigue, fever, stiff neck and GI upset, such as nausea. Even though gamma globulin may cause fever, it should always be reported to your doctor to make sure the fever is not due to an infection.
Cyclophosphamide (brand named Cytoxan)Cyclophosphamide is another, even more potent, immunosuppressant drug. It may be given intravenously or by mouth. However, it may cause more side effects when taken orally. Side effects may include nausea and vomiting, fatigue, hair loss, low blood counts and an increased risk of infection. Fatigue may increase with each treatment. Although the medication only takes an hour to administer, it is an all-day procedure because fluids need to be administered before and after cyclophosphamide. Because it can irritate the bladder, the patient must be well hydrated.
CellCept: An immunosuppressant, borrowed from transplant medicine.
Plaquenil: may be useful in treatment of rash in patients with dermatomyositis.
Rituximab (known as Rituxan): is administered intravenously and targets B-cells, which play a role in the inflammation of myositis. Rituxan has been used for people with Rheumatoid Arthritis but remains in clinical trials for myositis.
TNF blockers: suppress tumor necrosis factor proteins (TNF) that are associated with inflammation. The names of TNF blockers used in the treatment of myositis are:
Orencia (abatacept): has been used in the treatment of rheumatoid arthritis; usefulness in myositis is not yet known.
Interferon alfa blockade: drugs that block interferon; these are in early trials for patients with autoimmune conditions.
Vitamins and SupplementsBecause the drugs taken for myositis suppress the immune system, some patients have asked about vitamins and supplements that may boost the immune system.
Vitamins taken in normal doses, such as a one-a-day type of multivitamin, won't hurt you. Megadoses are not advisable. However, always consult your doctor before taking any new new medication, even an over-the-counter vitamins.
Never take any supplement that promises to boost your immune system, especially herbals such as echinacea. To take any substance that might boost the immune system would have the opposite effect of any drug you are taking for myositis. Some doctors believe that these supplements can actually cause flares in autoimmune diseases.
If you feel a cold, flu or other infection coming on, don't self-treat with over-the-counter medications. Call your doctor, especially if you are on high doses of prednisone or are taking some other immunosuppressant. The sooner your doctor starts treatment, the better the outcome.
Learn more about the Myositis Education and Support Group at HSS
Reviewed and Updated: 10/5/2009