An insight into cortisol and polymyositis control with steroid therapy.

In the present report we have developed a mathematical model to describe the processes involved during high steroid therapy. We have shown that the model can predict clinical observations as well as determine the optimum steroid regimen without relying on trial and error methods. The model incorporates rate processes that simplify the physiological complexity as a few representative steps. In this way, it is possible to simulate clinical observations and then to predict clinical outcomes due to drug concentrations or additional reactions within the body. Specific examples are provided from patients with polymyositis and Becker's disease. For the first time, we provide an explanation into the control of cortisol production, and determine an optimum prednisolone concentration in order to minimize steroid side effects while maintaining adequate control of muscle degradation.