Which is why asthmatics should be on the right meds that are most likely to help them. A controller for those with frequent attacks (singulair, inhaled steroids, etc.) and albuterol or similar med for a rescue inhaler. Primatene is terrible as a rescue inhaler, since it doesn't last long, and some patients get a very dangerous rebound effect. It also is more dangerous for those with heart conditions, etc. It just isn't a good drug.
I use it as a backup to the albuterol. When nothing else works it gdoes the job. I mostly eschew steroidal medication. people with heart problems should not use it..