Effect of diacerein as an add-on to metformin in patients with type 2 diabetes mellitus and inadequate glycemic control

Objective: To evaluate the effect of diacerein as an add-on to metformin in patients with type 2 diabetes mellitus (T2DM) and inadequate glycemic control. Materials and methods: A randomized, double-blind, placebo-controlled clinical trial was carried out on 12 patients with T2DM and inadequate glycemic control [glycated hemoglobin A1c (A1C) >= 7%] with metformin as monotherapy (>= 1500 mg per day) for at least the previous 90 days. Fasting and postprandial glucose were measured before and after the pharmacological intervention. A1C, lipid profile, creatinine and uric acid were also evaluated. After randomization, all patients continued with their dose of metformin. Six subjects received placebo and the other six volunteers took diacerein. Data were tested using the Wilcoxon signed-rank, Mann-Whitney U and chi-square tests. The Institutional Ethics Committee approved the study protocol. Results: After 90 days of diacerein as an add-on to metformin, there was a significant decrease in fasting glucose (196 +/- 79 vs. 149 +/- 70 mg/dL, p < 0.05), postprandial glucose (262 +/- 99 vs. 187 +/- 70 mg/dlL, p < 0.05) and A1C (8.4 +/- 2.0 vs. 6.7 +/- 1.7 %, p < 0.05). Conclusions: Diacerein as an add-on to metformin in patients with T2DM improved their glycemic control.