What is a little round green pill and has a k/8 on it?

Not Medical Advice: A green, round-shape pill with K 8 imprint has been identified as Oxycodone hydrochloride 15 mg.

Oxycodone is an opioid pain medication, it belongs to the drug class narcotic analgesics. It is used to treat moderate to severe pain. The extended-release form of this medicine is for around-the-clock treatment of pain. Learn more at Drugs.com.

In health news, U.S. health officials say that those at highest overdose risk from prescription painkillers, opioids, most likely get them from a doctor. The study also found 26 percent obtained drugs such as oxycodone or Vicodin from friends or relatives for free for non-medical uses, 23 percent bought the prescription painkillers from friends or relatives and 15 percent bought opioids from a drug dealer. Read more here.