1) Synthetic opioid 
Alphamethadol (INN), or α-methadol, also known as alfametadol, is a synthetic opioid analgesic. It is an isomer of dimepheptanol (methadol), the other being betamethadol (β-methadol). Alphamethadol is composed of two isomers itself, L-α-methadol, and D-α-methadol. The former compound, L-α-methadol, is an important active metabolite of levacet...