However admirable your intentions, legitimate medical clinics just can't accept your donations of prescription medicine once it has been dispensed to a patient. A moment's reflection would show why this is the case.

When you get a prescription filled at a pharmacy, you can safely assume that, barring physician or pharmacist error (that's a topic for its own thread of discussion!), you are getting a product of highly controlled composition and quantity, and which has been handled in a more or less formal and auditable manner by authorized persons for its entire voyage from manufacturer to you. These controls ensure that you get fresh, potent, and pure medicines that meet the standards established by law.

Once medicine is dispensed, however, this controlled chain of custody ends, and formal recordkeeping stops. Medicines that have been dispensed can be improperly stored, contaminated, substituted, etc; the law does not ordinarily regulate these things once the medicine is in the patient's hands. Somebody who gets the medicine from a patient second- (or third- or fourth-...) hand is in pretty much the same position as a person buying illicit drugs drugs from a street dealer: one of great uncertainty about the product and the potency. While your intentions are much different from those of the street drug dealer, you must recognize that, in many cases, your product is the same: second-hand prescription pills of uncertain pedigree!

I hope the foregoing clarifies the logic of laws that prohibit post-retail distribution of prescription drugs. Be assured that many drug manufacturers donate large quantities of medicine (of known pedigree) to charitable health organizations -- the same organizations who would be more than happy to take donations from you as well. Of money or volunteer skills, that is!

Stay pain free!