I use 2" X 3" zip lock bags. I then put them in snack or sandwich zip lock. 7 day trip I'll have 8 or 9 bags each with 1 day morning pills. Those 8 or 9 bags will go on a sandwich bag labeled am. Same procedure for pm, lunch etc. I'll fill another bag with aspirin and ibuprofen. Other bags with cold pills etc

No wasted space.

edited to add I couldn't post a picture. Search eBay or Amazon for small ziplock bags