I use this one from SentrySafe which is their small cashbox. Make sure you get this one and not the mini square one. Right now I only have two weeks of take homes but I have no doubt that this could carry 28.

ETA: When I just looked around at retailers when searching "SentrySafe small cashbox" I realized that there is a Deluxe version of the cashbox. It is different and would not work the way the linked one does.

This is the box that I have and nearly everybody at my clinic has also (probably because they sell them in Walmart).

The cash tray pops out, so you can just toss it. Comes with two keys which is nice - I keep one on my key ring for when I go to the clinic, and once on my nightstand where I store my box when I’m at home. It’s tall enough that the bottles can stand upright. I fit two weeks of take homes in it. I cut a simple grid out of styrofoam to keep my bottles upright so they don’t spill or leak (and would advise everyone always keep their bottles upright if possible - and you seem aware about this issue already). My clinic no longer does monthly take homes, but if they did, they would fit in there (and I probably wouldn’t need the grid to keep the bottles upright).

That said, this may not be a great box if you have any concerns at all about people illegally accessing your medication, because I suspect it would be stupidly easy to break into if somebody really wanted to get into it. Fortunately I live with my mother and nobody else so I don’t really have those concerns. If you do tho, you may want something a little more heavy duty.