Medicine
Medicines (whether in tablet, capsule, liquid, powder or any other form) can be damaging to the environment, so should never be disposed of down the sink or in your standard rubbish collection (where they will end up in landfill).
Out-of-date medicine may be ineffective or dangerous if used, so medicines that are no longer required should be disposed of rather than being hung onto for future use.
Unwanted or out-of-date medicine should be taken to a pharmacist for disposal. Any dispensing chemist in the UK will be able to take and dispose of it safely.
Packaging that is not necessary to contain the medicine (e.g. the box that contains a bottle of medicine) plus instructional leaflets, spoons or other dispensers, should be recycled in the appropriate way if no longer required.
I have no knowledge at present about how medicines are dealt with once the pharmacist has received them, and whether the packaging is recycled responsibly, so would be grateful of any information about this.