Ketamine is a prescription medication that has a role primarily as an anesthetic. Ketamine treatment leads to a dissociative state, helping people relax while also providing pain relief. When administered, ketamine can lead to changes in heart rate, breathing pattern, and airway reflexes. It can also influence blood pressure and treat depression. The different effects of ketamine are modulated by the size of the dose. Ketamine has a relatively quick onset of action and fades away relatively quickly. Ketamine exerts its impact by binding to the NMDA receptor, acting as an antagonist that blocks its activities. In addition, ketamine has been used as a recreational drug because of its hallucinogenic and associated impacts. It is frequently called Special K, and it is included on the World Health Organization's list of essential medicines.