A very noble thought. However, when it comes to medicines, it is not like the other commodities that one could donate and be used easily by the needy. Medicines are best prescribed by doctors with possibilities of them getting misused when available for free. I am so far not aware of any organizations that accept unused medicines as donations. There should not be a need for this here as the medicines are provided at very subsidized rates at all the medical centers run by the government and they are well within the reach of the common man. You may wish to check with some charity organizations though, just to be sure if they accept.