Patients who have taken either morphine with daily dose more than 120mg or Fentanyl with daily dose more than 50ug/hr 
Patients with significant abnormalities in hepatic or renal function which would, in the opinion of the investigator, prevent the patients involvement in the study 
Patients with significant clinical abnormalities in CNS, respiratory or cardiovascular function, which in the investigators judgement prevents participation in the study 
Patients who have taken antidepressants or anti-epileptic drugs, sedative hypnotics, selective serotonin reuptake inhibitor, short-acting analgesics, topical medications and anesthetics and/or muscle relaxants when taking Tramadol/Acetaminophen       
    

NCT00576173_exc_T1
Drug
morphine
NCT00576173_exc_T2
Multiplier
daily dose more than 120mg
NCT00576173_exc_T3
Drug
Fentanyl
NCT00576173_exc_T4
Multiplier
daily dose more than 50ug/hr
NCT00576173_exc_T5
Condition
abnormalities in hepatic function
NCT00576173_exc_T6
Condition
abnormalities in renal function
NCT00576173_exc_T7
Condition
abnormalities in CNS
NCT00576173_exc_T8
Condition
abnormalities in cardiovascular function
NCT00576173_exc_T9
Condition
abnormalities in respiratory function
NCT00576173_exc_T10
Drug
antidepressants
NCT00576173_exc_T11
Drug
anti-epileptic drugs
NCT00576173_exc_T12
Drug
sedative hypnotics
NCT00576173_exc_T13
Drug
selective serotonin reuptake inhibitor
NCT00576173_exc_T14
Drug
short-acting analgesics
NCT00576173_exc_T15
Drug
topical medications
NCT00576173_exc_T16
Drug
anesthetics
NCT00576173_exc_T17
Drug
muscle relaxants
NCT00576173_exc_T18
Drug
Tramadol
NCT00576173_exc_T19
Drug
Acetaminophen
NCT00576173_exc_T20
Scope
Tramadol/Acetaminophen
NCT00576173_exc_T21
Scope
antidepressants or anti-epileptic drugs, sedative hypnotics, selective serotonin reuptake inhibitor, short-acting analgesics, topical medications and anesthetics and/or muscle relaxants
NCT00576173_exc_T22
Temporal
when taking Tramadol/Acetaminophen
NCT00576173_exc_T23
Reference_point
taking Tramadol/Acetaminophen