What do you do with expired meds, does the pharmacy eat the loss?

It depends. In the US we have “prescription only” medication (things like antibiotics, diabetes meds, etc) as well as “controlled” medication (things like Norco, Xanax, morphine). With my former employer, we would go through the pharmacy and find non-controlled medication that was due to expire soon (3 or 6 months, I don’t remember) and send them back to our wholesaler for a partial credit. Packages had to be whole and unopened. With controlled medication, there is no sending back; the pharmacy holds the medication until it is actually expired, then sends it to be disposed of.

Do you mix and match pills with different expiration dates to fill a prescription? From different manufacturers?

Different expiration dates, yes, different manufacturers, generally no but if there’s no better option we would. In the US we generally fill from stock bottles containing several hundred or thousand pills, so one bottle can last a few months worth of prescriptions. When we go from one bottle to the next, the expiration dates between the two generally won’t be the same. When I left the company, we had a system that scanned the bottle we used and could read the expiration date; if the med expired in over a year, the label printed would just have an expiration date of 1 year from the current date. If it expired in less than 1 year, it would give a notification, and we’d manually enter the exact expiration date on the label.