Here are tips from the U.S. Food and Drug Administration on how to dispose of medications if you can't get to a drop-off location:
Remove them from their original containers and mix them with an undesirable substance, such as used coffee grounds, dirt or kitty litter (this makes the drug less appealing to children and pets, and unrecognizable to people who may intentionally go through the trash seeking drugs).
Place the mixture in a sealable bag, empty can or other container to prevent the drug from leaking or breaking out of a garbage bag.
FDA’s Ilisa Bernstein, Pharm.D., J.D., offers a few more tips:
Scratch out all identifying information on the prescription label to make it unreadable. This will help protect your identity and the privacy of your personal health information.
Do not give your medicine to friends. Doctors prescribe medicines based on your specific symptoms and medical history. Something that works for you could be dangerous for someone else.
When in doubt about proper disposal, ask your pharmacist.
Bernstein says the same disposal methods for prescription drugs could apply to over-the-counter drugs as well. Visit the FDA's How to Dispose of Unused Medicines page for more information.