Lefetamine (L-SPA; L-1,2-diphenyl-l-dimethylaminoethane hydrochloride) is a synthetic compound with analgesic and anti-inflammatory action, introduced in clinical practice in Italy and Japan as 'Santenol'. Santenol is available for oral (50 mg tablets1 and intramuscular (60 mg vials containing also lidocainel use. Animal studies have shown an analgesic effect and changes in EEG activity and O2 consumption of the nervous tissue. Lefetamine may be an opioid partial agonist. Lefetamine was first marketed in the 1940s as an opioid analgesic. Since withdrawal symptoms were observed during treatment, it became a controlled substance.

Lefetamine:
https://drugs.ncats.io/drug/4J9726V5Y9

A Bluelight Lefetamine Thread (2007):

• After the Second World War, the Japanese public, desperate to rebuild their shattered economy & infrastructure went on one almighty binge to help them work. Amphetamines were cheaper than food and allowed the beaverlike Japanese to work even harder. The drug they went for wasn't (meth)amphetamine, ritalin or anything like. It was this. It is reported to have both stimulant & 'opiate like' effects everywhere I read. It produces opiate tolerance & dependance that naloxone precipitates withdrawal syndrome. It is usually described as a 'partial agonist'. So, stimulant AND opiate. Sounds like a speedball with one chemical, doesn't it.

Lefetamine Thread (2007):
https://www.bluelight.org/xf/threads/lefetamine.287724/

A Reddit Lefetamine experience (37 comments):

• Around 1230 I took 20 mg to make sure I wouldn't die or have a seizure and went to the store. Got home around 130 and didn't feel anything but I wasn't dead so I took 40 mg more. About 20 minutes later there was a definite codeine feeling, like a small warmth in the limbs. Another 20 minutes and my mind is stimulated, but my eyes feel droopy and I'm super relaxed. I pour myself some vodka and mountain dew and relax for an hour. The feeling subsides or is taken over by the alcohol an hour later. I take another 40 mg at around 3. The warm opiate feeling returns and is here as I type this. I'm very glad that I was able to make this drug with relative ease. I can see how it could be addictive, and I'm very curious to try a dose of 100 mg all at once. The stimulant side of it is way more in the brain, the body is warm and fuzzy but the brain goes 100 miles an hour for a few minutes at a time.

• Back at baseline in about 4 hours. The stimulant effect is barely noticeable and only for about 30 minutes, the opiod effect is very nice and overpowering it. But there was none of the stimulant jitters I usually get, it was more mental than anything. Like a weak dose of Adderall for maybe an hour. Ill be taking 100 mg tomorrow so hopefully I can get some more of the stimulant effect.

Lefetamine Experience:
https://www.reddit.com/r/TheeHive/comments/gm8uv6/lefetamine_experience/

Lefetamine is a diphenylethanamine with opiate-like effects. While it has limited potential in detoxification treatment of opiate and methadone addiction, lefetamine is widely abused.

Lefetamine (hydrochloride) Safety Data Sheet (PDF 5 pages):
https://www.caymanchem.com/msdss/15566m.pdf

Dual effects of lephetamine on spontaneous and evoked neuronal firing in the somatosensory cortex of the rat:
https://www.opioids.com/lefetamine/index.html

• A stimulant painkiller
• Effects comparable to codeine.
• Invented in the 1940s
• It was abused in Japan during the 1950s
• It has been abused in Europe
• Some partial similarity to opioids