I began using a steroid-based asthma drug last summer, and got no performance benefit at all.
I was diagnosed with exercise-induced asthma and allergies this past summer after a lifetime without them (I'm 34 now). I started crashing in the middle of workouts that I was able to do a couple of weeks before. I started taking an allergy medicine and using an inhaler before workouts and races. I wasn't sure that I needed the inhaler, but figured that it might be an interesting amateur experiment in PEDs. I'm a 3:10 marathon, 39 minute 10k guy, so all the PEDs in the world won't make me competitive anyway. After ten weeks of good training (I thought) using the meds, I was no faster than the previous spring and had a series of lousy races.
Before this, I assumed that most elite athletes (like Haile and Paula) might be using asthma medicine to enhance performance, since so many have them. Now, I'm not so sure. They didn't help me.