IANAD but I think it means no food in your stomach when you take your meds. Since it can take a while to move food through your digestive system I would think that no food in the past 4-6 hours would constitute an empty stomach.
The population within the borough limits was 10,568 at the 2010 census. When combined with the surrounding Washington and Quincy Townships, the population of greater Waynesboro is 28,285. The Waynesboro Area School District serves a resident population of 32,386, according to 2010 federal census data.
The town of Waynesboro was laid out around the train stop and property was offered for sale by the railroad. By 1860, some 15 to 20 families called Waynesboro home, and businesses gradually began springing up to meet the needs of people living in the area.