The investigators include patients aged 18-80 years with acute (less than 1-month) low back pain with or without radicular signs, who do not have severe diseases (abscess, tumor, etc) in the background, already had CT or MRI scan during routine workup, and who have given written consent to participate in the study. Exclusion criteria are pregnancy, hypersensitivity to tolperisone in the history, severe liver or kidney disease, other severe diseases (abscess, tumor, etc) in the background of pain. The patients will be given 3 times daily 150 mg tolperisone or placebo in addition to standard therapy in a randomized double-blind design. Treatment will last for 14 days and a final follow-up is performed at 21 days. Clinical condition and biomarkers will be tested before treatment and at 14 days. Patients fill in a diary on a daily basis.
The main purpose of the trial is to identify biomarkers from the blood as well as electrophysiologic and morphometric features (chemical, electrophysiologic and ultrasound biomarkers) that reflect the intensity of pain and/or foretell the efficacy of pharmacological (non-surgical) treatment in patients with acute low back pain.