Tolerability of prolonged-release metformin (Glucophage® SR) in individuals intolerant to standard metformin — results from four UK centres

Advances in drug formulation have improved the tolerability of many commonly used agents. Metformin is recommended as initial drug therapy for type 2 diabetes and has proven long-term efficacy and safety. However, gastrointestinal (GI) side-effects of standard, immediate-release (IR) metformin often reduce medication adherence and limit dose titration. A prolonged-release metformin formulation may improve tolerability over its IR counterpart. We report the results of two prospective and two retrospective clinic-based evaluations of the tolerability of metformin in a total of 95 patients intolerant to standard IR metformin assessed over three to six months following a switch from IR to prolonged-release metformin (Glucophage® SR). Between 62% and 100% of patients from the centres tolerated the prolonged-release formulation. Glycaemia following the switch was improved or unchanged. Prolonged-release metformin represents a useful option for patients intolerant of standard IR metformin due to GI side-effects. This improved tolerance of prolonged-release metformin may improve medication adherence and thereby enhance treatment outcomes.