side effects - or not

I've recently changed from airomir salbutamol inhaler to ventolin salbutamol inhaler (basically cos asda sells ventolin without prescription LOL)

The airomir gives me quite noticable shakes which i didn't really mind as a compromise to easier breathing

I've been using the ventolin for a couple of weeks and not noticed any particular shakes

I've looked at the ingredients / strengths etc on both cannisters and can't find any difference so can't work out why one makes me shake and the other doesn't :-s

It's not a complaint against either inhaler or anything just an interesting (i think) observation