Xopenex inhalers in the USA have the identical strength as the generic product. In most countries, Xopenex uses the chemical name of levosalbutamol which is the same as levalbuterol. In addition, the strength of the inhaler in the USA is expressed as 45mcg which is the same strength as 50mcg in other countries due to where in the inhaler the measurement is taken. Both products are identical.