I use a range of inhalers with cats and they tolerate it surprisingly well.
You buy a device called a "spacer" whic fits over the end of the inhaler, and has a small clear face mask on the other end which goes over the cat's face. As the previous answer states, you spray the inhaler into the spacer and then allow the cat to breath the drug normally.
They most certainly WOULDN't tolerate the inhaler directly as anyone who remembers the old aerosol flea sprays will remember...