Prednisone mimics the action of a naturally occurring corticosteroid called cortisol, which is produced by the adrenal glands. Prednisone is prescribed for its anti-inflammatory properties, and in the case of muscular dystrophy, its long-term use can delay the progression of muscle weakness.
How prednisone works
Prednisone is metabolized by the liver into prednisolone, the active compound that produces the therapeutic effects. Prednisolone can easily pass through the cell membrane and get inside cells where it binds to glucocorticoid receptors in the cytoplasm. The glucocorticoid receptor-prednisolone complex then enters the cell nucleus where it regulates gene expression. For example, it shuts off the expression of pro-inflammatory genes and reduces inflammation.
The effects of prednisolone in the muscles include:
- Inhibition of muscle proteolysis (the breakdown of proteins).
- Stimulation of myoblast proliferation, which can help muscle growth and repair.
- Stabilization of muscle fiber membranes.
- Increase of muscle repair.
- Anti‐inflammatory or immunosuppressive effects.
Based on these effects, prednisone treatment in muscular dystrophy patients can:
- Improve muscle strength and delay the loss of walking ability by two to three years.
- Improve lung function, likely due to improved respiratory muscle strength.
- Reduce the need for scoliosis surgery.
- Delay the onset of cardiomyopathy caused by heart muscle weakness.
Prednisone in clinical trials
A randomized, double-blind, placebo-controlled six-month clinical trial in 103 boys, from 5 to 15 years old, with Duchenne muscular dystrophy (DMD) showed that prednisone administered at a dose of 0.75 mg per kg of body weight per day or 1.5 mg/kg/day increased the muscle strength and function of patients.
Two successive, six-month, randomized, double-blind, placebo-controlled trials found that 0.75 mg per kg per day was the optimal dose of prednisone for DMD patients. When this dose was continued in 93 boys for two years, followed by three years of observation while on doses of 0.5 and 0.6 mg/kg/day, a significant delay in disease progression and muscle function loss was observed for at least three years.
A number of side effects are associated with the long-term use of prednisone in muscular dystrophy patients. These include excessive weight gain, hypertension, behavioral changes, cataracts, and bone fractures because of osteoporosis. Calcium and vitamin D supplementation is therefore recommended for patients being treated long term with prednisone. Patients should contact their doctor before taking any supplements.
Last updated 07/09/2019
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