Opioid with rnonoarnine action is?
Tramadol REF: Principles and practice of palliative care and suppoive oncology By Ann M. Berger, John L. Shuster, Jamie H. Von Roenn page 51 "Tramadol is synthetic analog of codeine that binds to the MOR (Mu opioid receptor) and blocks reuptake of serotonin and nor epinephrine. As a result of monoamine action naloxone cannot completely reverse its respiratory depression"
Tramadol
Pentazocine
Pethidine
Meperidine