Urinary excretion of metformin in diabetic patients with and without tuberculosis.

BACKGROUND

Patients with concurrent diabetes mellitus (DM) and tuberculosis (TB) pose an increased risk of treatment failure in TB and management of DM is complicated. Anti-diabetic and anti-TB drugs may interact with on another other when co-administered. The role of anti-TB drugs on the excretion of metformin in urine has not been studied. Therefore, we carried out a study in DM patients with and without TB to compare the percentage of metformin excreted in urine.

METHODS

A total of 52 DMTB and 17 DM patients were recruited in this study from the Chennai Corporation Centres. DM and DM - TB patients were administered the prescribed anti-TB and anti-diabetic drugs (metformin (MET), glipizide (GLP),glimepiride (GLM),glibenclamide (GLB),rifampicin (RMP),isoniazid (INH), pyrazinamide (PZA) and ethambutol (EMB). DM and DMTB patients received metformin (MET) alone and in combination with sulphonylureas as diabetic drugs. The urine samples were collected from 0 to 8 hours after drug administration. Urine MET excreted in DM and DMTB patients were estimated by high performance liquid chromatography (HPLC) and percent dose was calculated.

RESULTS

The percent dose of MET excreted in urine in DMTB patients was significantly higher when compared to DM patients. There is significant difference in the percent dose of MET excreted among DM patients with and without sulphonylureas, values being 23.3 and 17.7% respectively (p = 0.044).

CONCLUSION

This is the first study to report on the percent dose of MET excretion in urine in patients with DM and DMTB receiving MET along with anti-TB drugs.