Answer:
Ketamine
Step-by-step explanation:
Ketamine is an anesthetic medication that, along with having sedative properties, also exhibits analgesic effects, also known as pain relief. It may also cause the patient's skeletal muscle to relax as well as some minimal respiratory depression. Because of these actions, ketamine is used as pain management medication despite its hallucinogenic capabilities.
Pharmaceutical grade MDMA is in use in hospitals, however it is not for analgesic purposes. Rather, psychiatric medical professionals use this medication for psychotherapy indications such as treatments for post-traumatic stress disorder (PTSD), eating disorders, and anxiety disorders, as a result of the Food and Drug Administration (FDA)'s classification of MDMA as a breakthrough therapy.
LSD is a Schedule I drug according to the Drug Enforcement Agency, deeming it a substance with no medical usage. However, it has been researched as a potential therapy for the treatments of alcoholism and depression, not pain relief.
Lastly, PCP once had medical usage as an intravenous (IV) anesthetic agent -- not as pain relief -- but use was discontinued after it was found to have side effects that were harmful to the brain, as is still seen in its recreational uses.