The comparator product was withdrawn from the brazilian market not being possible to conduct the design regarding initially planned.

The purpose of this study is to assess the efficacy end tolerability of a new drug containing the combination meloxicam and cyclobenzaprine (7,5/10mg) and the same components alone in the treatment of acute lumbago.

To assess the efficacy and tolerability of a new drug containing the combination meloxicam and cyclobenzaprine in the treatment of acute lumbago, compared to the same components alone.

Some eligibility criteria:

Have a normal X-ray of the lumbar spine for the age; Have a baseline score in the VAS higher than or equal to 40 mm

Inclusion Criteria:

• Sign, initial and date the Informed Consent Form (ICF);
• Be between 18 and 75 years old;
• Have acute lumbago with onset in less than 72 hours;
• Have a normal X-ray;
• Have a baseline score in the VAS higher than or equal to 40 mm;

Exclusion Criteria:

• Use of triptans;
• Use of monoamine oxidase inhibitors;
• Use of NSAIDs within the last week;
• Previous use of narcotics;
• Have any rheumatologic disease;
• Conditions of chronic pain;
• Have any significant chronic comorbidity;
• Previous history of gastrointestinal bleed or ulcers;
• History of allergy to any of the components of study medications;
• Recent history of a myocardial infarction, cardiac arrhythmia, cardiac conduction block or change, or congestive heart failure;
• Female patients who are pregnant or breastfeeding or who wish to become pregnant or who deny using safe contraceptive methods during the study will not be enrolled in the study;
• Have participated in another clinical trial within the last 12 months.