Complex sentence: These include but are not limited to etorphine & buprenorphine and usually have thebaine or oripavine as their precursor in synthesis (and are thus termed "thevinols" and "orvinols" respectively).
Split into simpler sentences: These include but are not limited to etorphine and buprenorphine. They usually have thebaine or oripavine as their precursor in their syntheses (and are thus termed "thevinols" and "orvinols", respectively).