Huang, W and Castelino, RL and Peterson, GM, Metformin usage in type 2 diabetes mellitus: are safety guidelines adhered to?, Internal Medicine Journal, 44, (3) pp. 266-272. ISSN 1444-0903 (2014) [Refereed Article]
Copyright 2014 The Authors
Aim: To (i) evaluate the prescribing patterns of metformin in patients with type 2 diabetes mellitus (T2DM) and determine the prevalence of contraindications to its use, especially renal impairment, and (ii) identify potential cases of lactic acidosis (LA) related to metformin usage.
Method: This retrospective study reviewed all patients with a diagnosis of T2DM and taking metformin who was admitted to a major teaching hospital over an 8-month period. Data including demographics, medical conditions, medications at admission and discharge, and relevant pathology results were extracted from medical records.
Results: A total of 301 patients (209 medical patients, 92 surgical patients) taking metformin were included. According to guidelines, approximately 31% and 21% of patients received metformin inappropriately (in the presence of contraindications or in excessive dosage) at admission and discharge, respectively. At admission, 65 patients (n = 301, 21.6%) on metformin had at least one contraindication to its use, and 42 patients (n = 254, 16.5%) were prescribed an excessive dosage according to their renal function. At discharge, 43 patients (n = 301, 14.3%) continued on metformin with at least one contraindication and 21 patients (n = 191, 11%) received an excessive dosage according to their renal function. Four patients had evidence of LA (plasma lactate concentration > 5.0 mmol/L and pH < 7.35) without clinical diagnosis.
Conclusion: Metformin was often used in patients with contraindications to its use, or in higher than recommended dosages. Reconsideration of the official prescribing information for metformin may be warranted as the risk of harm appears to be very low.
|Item Type:||Refereed Article|
|Keywords:||metformin, type 2 diabetes mellitus, inappropriate usage, contraindications, renal function|
|Research Division:||Medical and Health Sciences|
|Research Group:||Pharmacology and Pharmaceutical Sciences|
|Research Field:||Pharmaceutical Sciences|
|Objective Group:||Other Health|
|Objective Field:||Health not elsewhere classified|
|UTAS Author:||Huang, W (Miss Weiyi Huang)|
|UTAS Author:||Castelino, RL (Dr Ronald Castelino)|
|UTAS Author:||Peterson, GM (Professor Gregory Peterson)|
|Web of Science® Times Cited:||15|
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