A randomized double-blind clinical trial, to determine the effect of combined therapy of oral prolonged-release metformin/glimepiride in a single dosage form on fasting glucose and HbA1c. Patients will be included in this study are patients with diabetes mellitus and secondary failure to monotherapy. Will also assess the effect of combined therapy on the oral lipid profile (total cholesterol, LDL, HDL, VLDL, Triglycerides) and on the sensitivity and insulin secretion. We evaluate the clinical measurements, laboratory and safety during 3 months, through the allocation of subjects to three study groups (metformin, glimepiride and metformin extended release / glimepiride)