Lefetamine-related 1,2-diphenylethylamines were invented in the 1940s and showed weak analgesic activity.
It was investigated in Japan in 1950s. The l-isomer showed weak analgesic action comparable to codeine and antitussive action far weaker than codeine. The d-isomer showed no such activity but caused seizures in rats.
It was abused in Japan during the 1950s. In a small study in 1989 it showed some effect against opioid withdrawal symptoms without causing withdrawal symptoms itself. It was concluded that it may be an opioid partial agonist.
It has been abused in Europe, in 1989 a small study of 15 abusers and some volunteers found, that it had some partial similarity to opioids, that it produced withdrawal symptoms and had dependence and abuse potential to a certain degree.
Regulation may vary; it does not appear as either a Narcotic or Non-Narcotic under the US Controlled Substances Act 1970 
The Canadian Controlled Drugs and Substances Act was amended in 2016 to include the substance as a Schedule III substance. Possession without legal authority can result in maximum 3 years imprisonment. Further, Health Canada amended the Food and Drug Regulations in May, 2016 to classify Lefetamine as a controlled drug.
Some related pyrrylphenylethanones had analgetic activity comparable to morphine. Some pyrrole analogues were reported to have analgesic effects comparable to lefetamine and being devoid of neurotoxic properties.
^DE patent 1159958, Ogyu, K.; Fujimura H.; Yamakawa Y.; Mita I., "Verfahren zur Herstellung von antitussiv wirksamem l-1,2-Diphenyl-1-dimethylaminoaethan und dessen Salzen", issued 1963-12-27, assigned to Institut Seikatsu Kagaku Kenkyusho (Scientific Research Institute for Practical Life, Kyoto)
^Mannelli, P.; Janiri, L.; de Marinis, M.; Tempesta, E. (1989). "Lefetamine: New Abuse of an Old Drug -- Clinical Evaluation of Opioid Activity". Drug and Alcohol Dependence. 24 (2): 95–101. doi:10.1016/0376-8716(89)90071-9. PMID2571492.
^Janiri, L.; Mannelli, P.; Pirrongelli, C.; lo Monaco, M.; Tempesta, E. (1989). "Lephetamine Abuse and Dependence: Clinical Effects and Withdrawal Syndrome". British Journal of Addiction. 84 (1): 89–95. doi:10.1111/j.1360-0443.1989.tb00555.x. PMID2917208.
^Janiri, L.; Mannelli, P.; Persico, A. M.; Serretti, A.; Tempesta, E. (1994). "Opiate Detoxification of Methadone Maintenance Patients Using Lefetamine, Clonidine and Buprenorphine". Drug and Alcohol Dependence. 36 (2): 139–145. doi:10.1016/0376-8716(94)90096-5. PMID7851281.
^Massa, S.; di Santo, R.; Mai, A.; Artico, M.; Pantaleoni, G. C.; Giorgi, R.; Coppolino, M. F. (1992). "Pyrrylphenylethanones Related to Cathinone and Lefetamine: Synthesis and Pharmacological Activities". Archiv der Pharmazie. 325 (7): 403–409. doi:10.1002/ardp.19923250707. PMID1417455.
^Massa, S.; Stefancich, G.; Artico, M.; Corelli, F.; Silvestri, R.; Pantaleoni, G. C.; Fanini, D.; Palumbo, G.; Giorgi, R. (1989). "Synthesis, Neuropsychopharmacological Effects and Analgesic-Antiinflammatory Activities of Pyrrole Analogues of Lefetamine". Farmaco. Societa Chimica Italiana. 44 (9): 763–777. PMID2604832.