Opioid | Agonist property | Clinical ‘strength’ |
Morphine | Pure | Strong |
Oxycodone | Pure | Strong |
Hydromorphone | Pure | Strong |
Meperidine | Pure | Strong |
Fentanyl | Pure | Strong |
Methadone | Pure | Strong |
Buprenorphine | Mixed | Strong |
Nalbuphine | Mixed | Strong |
Pentazocine | Mixed | Strong |
Meptazinol | Partial | Strong |
Tramadol | Partial | Weak |
Codeine | Partial | Weak |