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IRCT20260627069967N1 IRCT 2026-06-29 Shahre-kord University of Medical Sciences Effect of Different Doses of Duloxetine on Chronic Low Back Pain Comparison of the effect of duloxetine at doses of 20, 30, and 60 mg on pain intensity in patients with chronic low back pain aged 40 to 65 years 2026-07-23 anticipated 135 Recruiting https://irct.ir/trial/91226 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Other design features: This is a randomized, parallel-group, single-blind (assessor-blind) clinical trial with three treatment arms. Because the prescribed dose is identifiable on the drug label, blinding of participants and the prescribing physician is not feasible; only the outcome assessor remains blinded to group allocation, Randomization description: Permuted block randomization with a 1:1:1 allocation ratio. Block sizes of 6 and 9 are used randomly. The unit of randomization is the individual patient. No stratification is applied. The random sequence is generated using Random Allocation Software (version 1.0). For allocation concealment, the assignment sequence is prepared by an independent colleague not involved in the intervention or outcome assessment, and placed in sequentially numbered, opaque, sealed envelopes (SNOSE). After obtaining informed consent and completing baseline assessments, the corresponding envelope is opened to reveal the group assignment, Blinding description: Due to the nature of the intervention, with the drug dose clearly identifiable on the medication packaging, participants and the treating physician (principal investigator responsible for prescribing and patient visits) are not blinded to group assignment. All patients are informed that they are participating in a clinical trial and will receive one of three doses of duloxetine, and written informed consent is obtained. The outcome assessor (measuring pain intensity via VAS and recording adverse events) is a trained independent colleague not involved in patient care, who remains blinded to treatment allocation. To maintain assessor blinding, patients are instructed not to disclose their dose during assessment sessions. Group allocation is not recorded on assessment forms or case report files used by the assessor; groups are identified only by a unique code that does not reveal the dose. After data collection, the database is anonymized by another person and handed over to the statistician for analysis without group identifiers. No formal Data Safety and Monitoring Board (DSMB) has been established, but study progress and serious adverse events are continuously monitored by the supervising professors. The authors drafting the manuscript will remain blinded to group allocation until the database is locked and the code is broken. 3 Chronic Back Pain. Intervention 1: Intervention group: Duloxetine hydrochloride (manufactured by Actoverco) at a dose of 30 mg, one oral capsule daily, for 6 weeks. Intervention 2: Intervention group: Duloxetine hydrochloride (manufactured by Actoverco) starting at 20 mg once daily in week 1, increasing to 40 mg once daily in week 2, and then 60 mg once daily from week 3 through week 6. All capsules are taken orally once daily. Intervention 3: Control group: Duloxetine hydrochloride (manufactured by Actoverco) at a dose of 20 mg, one oral capsule daily, for 6 weeks. 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 A decision on this matter will be made soon with the supervisor and the research assistant.
public Sajjad Radfar
No.41, west Molavi Ave., Shahrekord
Shahrekord Iran (Islamic Republic of) 8815713471 +98 31 4263 6416 Sajjadradfar75@gmail.com Shahre-kord University of Medical Sciences scientific Sajjad Radfar
No.41, west Molavi Ave., Shahrekord
Shahrekord Iran (Islamic Republic of) 8815713471 +98 31 4263 6416 Sajjadradfar75@gmail.com Shahre-kord University of Medical Sciences Iran (Islamic Republic of) Chronic low back pain diagnosed by a rheumatologist Discopathy (degenerative disc, disc protrusion or herniation) Exclusion of other specific causes of low back pain (referred pain, recent trauma, fractures) confirmed by a rheumatologist Age 40–65 years Non-pregnant and non-lactating No current use of psychiatric medications 40 years 65 years Both Confirmed aortic aneurysm Unavailability for follow-up visits Known hypersensitivity to duloxetine Unwillingness to participate M54.5 Low back pain Treatment - Drugs Treatment - Drugs Treatment - Drugs Intervention group: Duloxetine hydrochloride (manufactured by Actoverco) at a dose of 30 mg, one oral capsule daily, for 6 weeks Intervention group: Duloxetine hydrochloride (manufactured by Actoverco) starting at 20 mg once daily in week 1, increasing to 40 mg once daily in week 2, and then 60 mg once daily from week 3 through week 6. All capsules are taken orally once daily Control group: Duloxetine hydrochloride (manufactured by Actoverco) at a dose of 20 mg, one oral capsule daily, for 6 weeks. Pain intensity score measured by Visual Analogue Scale. Timepoint: Before intervention (baseline) and weeks 2, 4, and 6 after treatment initiation. Method of measurement: Visual Analogue Scale: a 10-centimeter line where 0 represents "no pain" and 10 represents "worst possible pain"; the patient indicates pain intensity on the line. Standardized tool with confirmed validity and reliability. Incidence of any adverse events including nausea, dizziness, somnolence, fatigue, sweating, dry mouth, constipation, and diarrhea. Timepoint: Weeks 2, 4, and 6 after treatment initiation. Method of measurement: Direct patient interview at each visit and recording of any experienced adverse events on an adverse event checklist. Shahre-kord University of Medical Sciences Approved 2024-06-16 Research Ethics Committees of School of Medicine - Shahrekord University of Medical Sciences Kashani St, Shahrekord University of Medical Sciences, Shahrekord, Iran Shahrekord Chahar-Mahal-va-Bakhtiari Iran (Islamic Republic of)