My PCP prescribed 2 20 mg tabs daily for five days for breathing problems. Shortness of breath. It worked! Now what do I do? I m a 78 yo male, with many maladies, including, but not limited to: Parkinson s, Heart disease, Osteo-arthritis, detached retinas, blood clots et al. I m confined to a wheelchair. I recently had a chemical stress test that concluded that I showed a narrowing of an artery going to my heart that disappeared when I transferred to my chair. I try to excercise 3 ts./ wk.