This is one area that needs to be continued to be handled by humans themselves. The airspace is only a part of the problem. There are couple of other problems that I can foresee.
First, hospitals get shipments of some extremely powerful drugs and medications. These products do not need to fall into the wrong hands should an error with the drone occur.
For shipments being delivered to private addresses, I feel as if HIPPA could be affected. Not only that, some drugs and medications are temperature sensitive. A drone is not going to check to see if it was delivered to the correct address (for HIPPA PRIVACY) or if there is even anybody home to receive the shipment. (For temperature controlled, the possibility of needing a signature upon receipt, or HIPPA). Drones cannot check if they are delivering to right address or if there is even someone at the programmed address to sign for the package should that be necessary.