I don't think you're supposed to flush or put pills down the drain, as they can contaminate. One little px won't but if everyone makes a habit of it then there are issues. I'd throw them away, maybe amongst a load of messy gone bad leftovers or something. Or call the pharmacy they'll know what to do.
As for paint, cities usually have hazardous dump days, when you can drop off paint, batteries, questionable materials etc at convenient (???) locations? Can you call your cities 411 line? Actually in Charlotte it's 311, wierd, or look it up on the city sanitation website.
Of course you always have the option of selling them on the street?

kekeke