The purpose of this study is to investigate the effects of a fixed dose combination of diclofenac and eperisone hydrochloride compared with plain eperisone hydrochloride in patients with low back pain.

This study is an observer-blind, prospective randomized, controlled study to evaluate efficacy and safety of fixed dose combination of eperisone hydrochloride 50 mg and diclofenac sodium 50 mg three times daily with plain eperisone hydrochloride 50 mg three times daily in patients with musculoskeletal spasm associated with low back pain. A total of 240 adult patients of either sex, 120 patients in each arm, who fulfill the inclusion and exclusion criteria will be included in this study. The patients will be evaluated at Days 3, 7 and 10 of the study visit for efficacy and safety. The efficacy evaluation includes objective parameters like Finger-to-Floor distance, Lasegue's sign, tenderness of par vertebral muscles, lumbar and dorsal hypermyotonia, leg tendon reflexes, need for rescue medication and subjective parameters like improvement in lumbar cinesalgia, pain in lower extremities, sensory disturbances of lower limb, and Global Assessment of Response to Therapy (PGART). Patients will be evaluated for safety on the clinical adverse events reported during the study period, sedation on drowsy alert scale and Global Assessment of Tolerability to Therapy (PGATT). The patients will also be evaluated for laboratory safety as assessed by measuring laboratory parameters for hemogram, renal and hepatic parameters.

Inclusion Criteria:

• Patient of either sex between 18 to 60 years of age
• Patients with confirmed diagnosis of Acute Musculoskeletal spasm with Low

Back Pain due to any of the following causes:

1. Spondylosis deformans

2. Prolapsed Intervertebral Disc (PID)

3. Muscle Sprains with spasms

   • Patients willing to take the medications as directed and willing to come for the follow-ups
   • Willing to comply with the protocol requirements
   • Willing to give the written informed consent

Exclusion Criteria:

• Patients associated with other lumbar spinal tract conditions such as spondylitis, fracture, cancers, severe arthritis and osteoporosis.
• Muscular diseases such as myositis, poliomyelitis, muscular dystrophy and myotonia.
• Other known systemic diseases affecting the neurological or endocrine.
• Patients with moderate to severe hepatic impairment (defined as increase in serum bilirubin, serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) by >2.5 times the upper reference level of the laboratory values) and renal impairment (defined as increase in serum creatinine and Blood urea nitrogen by >2.5 times the upper reference level of the laboratory values).
• Patients who had taken any form of skeletal muscle relaxant in the previous 7 days.
• Pregnant / Lactating woman or women of child bearing potential not following adequate contraceptive measures.
• Patients with known hypersensitivity to ingredients of study/active comparators.
• Patients with any previous history of or current episode of cardio-vascular disorders.
• Subject known to be having any of the following disorder: renal failure, bulimia, hypo and hyperthyroidism, nephrotic syndrome, anorexia nervosa, biliary obstruction, severe cardiac dysfunction.
• Uncontrolled diabetes mellitus or any other metabolic disorder.
• Pediatric and pregnant patients.
• Patients with history of alcoholic/substance abuse.
• Treatment with any investigational drug in the preceding 4 weeks.
• Patients with active or recent history of, inflammatory diseases of the gastrointestinal tract such as peptic ulcer, gastritis, regional enteritis, or ulcerative colitis.
• Patients in whom acetylsalicylic acid (ASA) or other non-steroidal anti-inflammatory agents (NSAIDs) have induced asthma, rhinitis, urticaria or other allergic manifestations.
• Any other condition that, in the opinion of the investigator, does not justify the inclusion of the subject in the study.