Alfentanil - chemical structure
By Harbin / Public domain
Buprenorphine - chemical structure
By Harbin / Public domain
Codeine - chemical structure
By NEUROtiker / Public domain
Fentanyl - chemical structure
By Harbin / Public domain
Heroin - chemical structure
By NEUROtiker / Public domain
Hydrocodone - chemical structure
By Yikrazuul / Public domain
Hydromorphone - chemical structure
By Yikrazuul / Public domain
Meperidine - chemical structure
By Ben Mills / Public domain
Methadone - chemical structure
By Calvero / Public domain
Morphine - chemical structure
By NEUROtiker / Public domain
Tramadol - chemical structure
By Harbin / Public domain