IRCT20120215009014N376 IRCT 2021-01-22 Hamedan University of Medical Sciences Effect of N-acetyl cysteine supplementation versus placebo on clinical outcomes in women with chronic pelvic pain syndrome Effect of N-acetyl cysteine supplementation versus placebo on clinical outcomes in women with chronic pelvic pain syndrome: a double-blind randomized clinical trial 2021-04-21 anticipated 60 Complete https://irct.ir/trial/53802 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: The patients will be randomly assigned to intervention and control groups using block randomization. For this purpose, we will prepare four sheets of paper, writing on two sheets the name of the intervention and on the other two sheets the name of the control. The paper sheets will be pooled, placed in a container, and randomly drawn one at a time for each patient without replacement until all four sheets are drawn. The four paper sheets will be then placed back into the container, and this action repeated until the sample size is reached, Blinding description: The shape of the medications and placebos will be perfectly the same. Therefore, patients will be unaware of the type of intervention. The physician who will examine the patients will not be aware of the intervention. Thus, the trial will be run as triple-blind. 3 Chronic pelvic pain syndrome. Intervention 1: Intervention group: Amitriptyline 25 mg daily plus N-acetyl cysteine tablets (manufactured by Osweh Pharmaceutical Co., Tehran, Iran) 600 mg every 12 hours for 2 months. Intervention 2: Control group: Amitriptyline 25 mg daily plus placebo tablets (manufactured by Shahid Beheshti School of Pharmacy) every 12 hours for 2 months. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is It depends on the situation and the results of the study as well as the approval of the financial supporting organization.