Assessing the appropriate use of metformin in an inpatient setting and the effectiveness of two pharmacy-based measures to improve guideline adherence.

Objective: To demonstrate the level of compliance to metformin-prescribing guidelines and to evaluate the effectiveness of 2 pharmacy-based interventions.

Methods: Retrospective chart review of all inpatients who had received at least 2 doses of metformin while hospitalized. Two cohorts of patients had chart audits-one group (group A) hospitalized between March and August of 2003 (487 patients) and one group (group B) hospitalized between August of 2005 and January of 2006 (370 patients). In December of 2003, the pharmacy inserted a safety alert in the electronic ordering system and mailed a printed safety alert to all clinical staff outlining the contraindications and precautions concerning metformin use.

Results: More than two-thirds (69.3%) of the charts reviewed demonstrated that metformin was used in accordance with the prescribing guidelines. Surgical procedures, intravenous contrast use, and elevated serum creatinine levels accounted for the greatest percentage of guideline violations. The prescribing guidelines were violated 27.4% (47/137 charts) of the times in group A and 34.3% (40/146 charts) of the times in group B.

Conclusions: The significance of this study is that metformin is often given in spite of the presence of contraindications to its use. Two pharmacy interventions were ineffective in decreasing the guideline violation frequency in a group of patients who were prescribed the drug.