I wish there was a mod crazy option. You really think that any and every pharmacy that a person might get their prescription filled at -- most of which are commercial entities without ties to a hospital -- are going to individually put serial numbers on pills that link them to the person getting the prescription filled? I'll give you a hint, I've worked at a pharmacy and they definitely do not do this. Let alone track fingerprints. There is a bottle filled with pain killers on the shelf. When a prescription comes in, the pharmacist or pharmacy tech grabs that bottle, and counts out the number of pills prescribed into a new bottle, which is given to the customer.
Now the pills might contain a serial number that ties them back to a specific batch, which would tie them to a pharmacy and they could pull up a log of customers who had prescriptions filled from that batch and narrow it down reasonably well (even to 1 person if that person was the only one who got a prescription filled from that batch) but there is no guarantee that it can be narrowed down to 1 specific person as there is no individual tracking information on the pills.