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 most monthly precipitation in Waynesboro occurs in June with 4.1 inches. The air quality index in Waynesboro is 17% better than the national average. The pollution index in Waynesboro is 218% worse than the national average.