Twelve male or female adult non-smoking subjects aged 18-40 years with body weights within ±15% of the ideal weight for height will be recruited for the study. The subjects will be submitted to physical examination, determination of previous or present chronic diseases, and comprehensive laboratory testing to ascertain that they are in good health. The subjects will fill in a modified Finnish version of the Abuse Questions (Michna et al. 2004) to assess their vulnerability for opioid abuse. Laboratory screening will include CBC (including hemoglobin, hematocrit, differential WBC, platelet count), SGOT, SGPT, alkaline phosphatase, BUN and creatinine, and for women a pregnancy test. Urine will be screened for glucose, proteins and drugs with addiction potential. Blood pressure in sitting position must be within normal limits. Base line ECG must be normal.