IRCT201404297829N5 IRCT 2016-11-27 Vice chancellor for research Mashhad University of Medical Sciences Comparison of two analgesic methods in control of Post-operative pain Comparative study of the analgesic effect of Morphine patient control analgesia pumps and Fentanyl Trans-dermal patches in acute post operative pain management in addicted patients 2014-01-20 anticipated 300 Complete https://irct.ir/trial/8279 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Other design features: Blinding: due to the intervention of the study, blinding for patients is impossible. The nurse who is responsible for the pain interview and patient information and also the statistician responsible for analyzing the data were blinded to the intervention. Randomization: using a random number table, patients were randomly allocated into two groups. N/A Acute post operation pain. Intervention 1: Morphine pump group: 100cc pumps will be filled with 20mg morphine Diluted in 100cc normal saline. It will be set on 1mg/h infusion rate. One bolus dose could be added by the patients if he/she needs more analgesia. It was made by AutoFuser Disposable Pain Pump Product, Ace Medical Co, Gyeonggi-Do, Korea. Intervention 2: Fentanyl patch group: Fentanyl patches with total dose of 25mg will be attached upon the patients' arm 18h before the surgery due to 18h delayed action of them. It was made by Fentanyle ITS; Ionsys TM, Janssen Pharmaceutica NV, Beerse, Belgium.