On this edition of ST on Health, we learn about Narcan, a/k/a Naloxone, which is a well-known and widely used opioid antagonist --- meaning, it's a drug that works to quickly block the effects of heroin, morphine, and similar opiates/sedatives. Narcan is thus administered in many instances where a person is experiencing (or has just recently experienced) a drug overdose; in this way, Narcan, which was originally developed in the 1960s, is thought to have saved some 50,000 lives nationally.