There is absolutely no legitimate reason to give someone suffering from clinical depression and kleptomania naloxone. Naloxone is a pure u-opioid antagonist, meaning it blocks opioids from binding to the opioid receptors in the brain and central nervous system. It is mostly used to reverse the effects of an opioid overdose, and is also used in combination with some kinds of orally administered opioids to prevent abuse.
The pharmacy that Doc gets the medication 10K needs is an in house pharmacy for this asylum, yet for some reason they have veterinary medications in stock. Like the Rimdayl for example is a NSAID used to treat pain in cats and dogs.