Adherence, satisfaction, and experience with metformin 500 mg prolonged release formulation in Indian patients with type 2 diabetes mellitus: a postmarketing observational study

PURPOSE: The aim of this study was to understand patient adherence, satisfaction, and experience with the smaller sized metformin 500 mg prolonged release (PR) tablet that has been manufactured with the help of technological advancement (Gluformin I 500 mg), in comparison with metformin 500 mg extended-release (ER) tablet, in patients with type 2 diabetes mellitus (T2DM). PATIENTS AND METHODS: In this postmarketing observational study, T2DM patients who were on a stable dose of metformin 500 mg PR tablet for at least 1 month and had previously received metformin 500 mg ER tablet were recruited from 50 sites in India. The medication adherence and patients’ experience, satisfaction, and perception with metformin 500 mg PR tablets were compared with metformin 500 mg ER tablets. The patients’ experience was determined based on the external appearance of tablet, ease of swallowing, the presence of gastrointestinal discomfort, and ghost pill effect. RESULTS: A total of 1,000 patients were enrolled. The majority had medium adherence to metformin 500 mg PR tablet (54%) and did not report swallowing difficulties (66.2%) due to its small size (64.4%) and oval shape (64.3%). The PR formulation of metformin was more acceptable than ER formulation due to no aftertaste (63%). The ghost pill effect was reported in 0.7% of patients with metformin 500 mg PR tablet against 8.5% with ER tablet. More than 60% of patients were “comfortable” (67.9%), had “much effect on their well-being” (61.8%), and were “satisfied” (69%) with metformin 500 mg PR tablet compared with ER tablet. Patient’s dissatisfaction (42.7%) and taste (24.9%) were the common reasons cited by physicians and patients, respectively, for changing the treatment from metformin 500 mg ER to metformin 500 mg PR formulation. A total of 10 adverse events (nonserious) were reported, and all of them were resolved. CONCLUSION: The technologically advanced formulation of metformin 500 mg PR tablets is more effective than that of metformin 500 mg ER tablets in improving adherence, compliance, satisfaction, and perception to medication in Indian patients with T2DM.