Sucampo Pharmaceuticals and Takeda Pharmaceuticals North America announced that Amitiza (lubiprostone) 8 mcg capsules are now available by prescription in pharmacies across the US for the treatment of irritable bowel syndrome with constipation in women 18 years and older. Amitiza 24 mcg capsules have been available by prescription to treat chronic idiopathic constipation in adults since 2006.