Effect of N-acetyl cysteine versus placebo on clinical outcomes in patients with acute radicular lumbar pain: a double-blind randomized clinical trial

To assess the effect of N-acetyl cysteine versus placebo on clinical outcomes in patients with acute radicular lumbar pain

This is a double-blind randomized clinical trial, phase II, in which 60 eligible patients will be randomly assigned to the intervention and control groups

The eligible patients with acute radicular lumbar pain referring to the Sina Hospital in Hamadan city during the study period will be enrolled in the trial and will be randomly assigned to the intervention and control groups through the block randomization. This trial will be double-blinded so that neither patients nor the physician examining the patients will be aware of the intervention.

Inclusion criteria: Age of 18 to 65 years, Acute lumbar radicular pain due to disc herniation, A minimum pain intensity score of 4 or more based on the VAS, A minimum functional disability score of 30 or more based on disability index questionnaire, Symptoms start between the last 2 to 12 weeks, Exclusion criteria: Taking herbal medications or products or other supplements in the last 3 months, Spinal canal stenosis or intervertebral disc degeneration, Patients with progressive and severe motor symptoms, History of neuropathy for other reasons, History of lumbar surgery, Existence of any malignancy, Chronic liver or kidney disease, Hypersensitivity to N-acetyl cysteine

Intervention group: Routine treatment plus N-acetyl cysteine tablet (manufactured by Osveh Pharmaceutical Co.) 600 mg every 12 hours for 2 months Control group: Routine treatment plus placebo tablet (manufactured by School of Pharmacy, Shahid Beheshti University) every 12 hours for 2 months

Primary outcome: Functional disability, the severity of pain, response to treatment Secondary outcome: Gastrointestinal or systemic adverse effects

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.

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