How is your rubbish disposed of - incinerator or landfill? If it's incinerated I think it's ok to put them in the rubbish, with caps tight on the bottles so they don't leak in transit. But I wouldn't put them in the bin if the rubbish goes into landfill.
I wouldn't pour them down the drain either as they'll end up in a river or sea.
Dechlorinator should be OK poured on a bare patch of earth in the garden, but the meds depend on exactly what they are.