Agree with above post. Your doc may have prescribed as a diagnostic/therapeutic trial for some symptoms, but ran out of time to explain it all to you. I'd get in touch with the person who prescribed it to you and ask them, as inhalers aren't typically used in this situation.
I was also confused when the physician said she was prescribing an inhaler, the main things I complained about was a feeling of pressure in my chest and my heart feeling as if it was beating faster, but too softly, then skipping a beat and beating harder as if to compensate for the lost beat. I also mentioned how a little over 2 weeks ago I had a severe attack that was causing my muscles to twitch and spasm and i was sweating. The papers from my discharge say asthma but asthma was never mentioned during the visit.