It would not be a drug, but a solution of self replicating medical nanomachines that would serve a number of functions.
– search and elimination of harmful bacteria, viri, parasites and chemicals as well as cancerous cells.
– cell/tissue regeneration and rejuvination
– genetic optimisation and subsequent cell restructuring to eliminate heredetary and developmental illnesses, conditions as well as susceptibility to diseases
– enhancement of existing and installation of new micro and macro physical abilities, such as
—- improved strength, speed, stamina, cell regeneration, vision, hearing, smell, taste, tactile sense, intelligence, memory
—- new features, such as photosynthesis, solar electric power generation, zero point energy generating cell organelles, digital memorybanks consciously accessible by the mind, auxilliary processors to speed up thinking, active zoom for the eye, full EM spectrum range for the eye with sound source overlay and overlay of other data, like the medical, chemical and physical status of the object you are looking at and environmental variables fed from a new sensor array, full 3 dimensional awareness, even beyond and inside obstacles, technology based telepathy, epidermal forcefields, full replacements of lost limbs and organs within a few minutes, including vital organs like hearts, lungs, the brain, etc., a bodywide redundant backup system for the brain’s memory
How is that for a start?