Ketamine is a chemical compound used as an anesthetic in humans and animals.1,2 It was developed decades ago as a less toxic alternative to the drug phencyclidine (PCP), which was also developed as an anesthetic. A ketamine derivative, esketamine (under the brand name Spravato®), is approved by the U.S. Food and Drug Administration (FDA) for treatment-resistant depression in adults. There is also illicitly manufactured ketamine, sold as a liquid or off-white powder, and commonly called Special K, K, Super K, or Vitamin K.4