$8 billion by 2017. [ 15 ] [ edit ] Manufacturers The largest manufacturers of inhalers are GlaxoSmithKline (makers of the Advair Discus (a DPI), Merck , AstraZeneca (makers of Pulmicort and Symbicort) and Boehringer-Ingelheim (makers of Atrovent, Combivent, and Spiriva). BI, GSK, Merck, and AstraZeneca manufacture the medication being delivered