Opioid analgesics

1. According to ring structure

A . Phenanthrene derivatives

Morphine

Codeine

Thebaine

B . Benzo-isoquinoline derivatives

Papaverine

Noscapine

11. According to synthesis

A. Natural opium alkaloids

Morphine

Codeine

B. Semi synthetic opium alkaloids

Heroine

Pholcodeine

C. Synthetic opiods

Pethidine

Methadine

Tramadol