Huh. I never knew you couldn't throw it away (I knew not to flush it, though.)
It's safer to dispose of it properly through a pharmacy because if you just put it in the bin then anyone could get their hands on it (i.e. pets, children) and decide to take some of it (especially important if it's prescription medication). Also, it can still end up damaging the environment later down the line if it ends up in a landfill site and then leaks out into the soil.
I have some stuff I could do that with. Do I need to take it out of the packaging? I've got some old cold meds in blister packs (OTC stuff).
Usually people just come in with a plastic shopping bag with their medicines inside - some still in their boxes, some in blister packs, some in bottles etc.... just bring it in whatever packaging it's already in
(don't take it out of the blister packs or anything though).