Treatments and drugs

By Mayo Clinic Staff

Although there's no cure for polymyositis, treatment can improve your muscle strength and function. The earlier treatment is started in the course of polymyositis, the more effective it is, leading to fewer complications. However, as with many conditions, no single approach is best; your doctor will tailor your treatment strategy based on your symptoms and how well they respond to therapy.

Corticosteroids

For most people, the first step in treatment for polymyositis is to take a corticosteroid medication. Usually for polymyositis, the chosen medication is prednisone.

Corticosteroids are medications that suppress your immune system, limiting the production of antibodies and reducing muscle inflammation, as well as improving muscle strength and function.

Your doctor may prescribe a very high dose to begin with, and then decrease it as your signs and symptoms improve. Improvement generally takes about two to four weeks, but you may take the medication for several months. Prolonged use of corticosteroids can have serious and wide-ranging side effects, which is why your doctor may gradually taper the dose of medication down to low levels.

Because of the potential for serious side effects, your doctor may recommend supplements to combat them, such as calcium and vitamin D, and may prescribe medications to help protect your bones.

Additional immunosuppressive therapies

If a corticosteroid medication doesn't seem to be working effectively in your case, as a secondary approach your doctor may recommend that you add or switch to another medication:

  • Corticosteroid-sparing agents. When used in combination with a corticosteroid, a corticosteroid-sparing medication can decrease the dose and potential side effects of the corticosteroid. These medications include azathioprine (Azasan, Imuran) or methotrexate (Trexall, Methotrexate, Rheumatrex). Your doctor may prescribe azathioprine or methotrexate initially along with prednisone if your disease is very progressive or if you have complicating factors. Some doctors prescribe these medications as a first line treatment for people in whom corticosteroids aren't recommended. 
  • Intravenous immunoglobulin (IVIG). IVIG is a purified blood product that contains healthy antibodies from thousands of blood donors. The healthy antibodies in IVIG can block the damaging antibodies that attack muscle in polymyositis. This treatment is given as an infusion through a vein. The effects of IVIG are beneficial, but don't last very long. Repeat infusions every six to eight weeks are often necessary.
  • Other immunosuppressive medicine. Tacrolimus (Prograf) is a transplant-rejection drug that may work to inhibit the immune system. Tacrolimus is often used topically to treat dermatomyositis and other skin problems. When taken orally, it may be helpful in treating people who have polymyositis complicated by interstitial lung disease.

    Immunosuppressants, such as cyclophosphamide (Cytoxan) and cyclosporine (Gengraf, Neoral, Sandimmune), may improve signs and symptoms of polymyositis and interstitial lung disease.

Biological therapies

If your case is severe and other treatment options have failed, your doctor may recommend one of these investigational medications as a third line approach to treating polymyositis:

  • Rituximab (Rituxan) has been studied in small numbers of people with polymyositis and dermatomyositis and shown to improve muscle strength, lung involvement and skin rash.
  • Tumor necrosis factor (TNF) inhibitors, such as etanercept (Enbrel) and infliximab (Remicade), are medicines that target key proteins associated with inflammation.

However, there aren't many scientific studies to date about the effectiveness of these agents on polymyositis. If your doctor prescribes one of these medications, you'll be closely monitored for side effects. These medications can be expensive and, because they're experimental for treating polymyositis, may not be covered by insurance.

Other treatment approaches

Besides taking medication, your doctor may recommend additional therapies for polymyositis treatment, including:

  • Physical therapy. A physical therapist can show you exercises to maintain and improve your strength and flexibility and advise an appropriate level of activity.
  • Dietetic assessment. Later in polymyositis, chewing and swallowing can become more difficult. A registered dietitian can teach you how to prepare easy-to-eat foods.
  • Speech therapy. If your swallowing muscles are weakened by polymyositis, speech therapy can help you learn how to compensate for those changes.
Jul. 07, 2011