First. check with your doctor to see that you are not being overprescribed. Discuss with your doctor the types and amounts of medication you are taking, as well as the sheer number of pills. You will receive the most benefit from the lowest possible dose of medication that will alleviate your symptoms or cure your disease. Anything more powerful is stressful for your body and can even derail the healing process. It's also more effective to take more pills per day, at a lower dose, than one or two pills per day at a higher dose. (Another good idea is to check with your pharmacist--even if you don't buy all your prescriptions at the same pharmacy, it's important that your pharmacist know every drug and dosage that you are taking. Pharmacists are trained to spot drug interactions and can warn you of a possible contraindication that your doctor may not be aware of.)
Go through your medicine cabinet and check your medications. Gather up any expired medications and take them to your pharmacy, where they will be disposed of safely. Or see if your community has a "Drug Take-Back Day," where they will accept medications without an ID, and without looking at them. Those will also be disposed of safely.
If you have medications left over with a few months until the expiration date, you can send them to the Health Equity Project, a nonprofit foundation that takes unused, unexpired medications and ships them to people around the globe who are in desperate need.
You may also want to invest in a good-quality water filter, and use it to filter all the water in your house. You can either buy a whole-house filter, or a separate filter for each tap, as well as your shower and your icemaker and refrigerator water dispenser, if you have one. Don't forget the washing machine, too, because drug residues can be deposited on your clothing and then leach into your skin. Check the replacement dates on the filters and make sure they are replaced on schedule, or your water filter will not have the desired effect. While a water filter may not remove everything in your water, it will certainly do no harm and may help your water quality significantly.
With these few simple steps, you can assure your drinking water safety and help people all over the world, at no cost to yourself. For more ways to protect the environment, check other things you can recycle.