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Novel assay of metformin levels in patients with type 2 diabetes and varying levels of renal function: clinical recommendations.

Frid A, Sterner GN, Löndahl M, Wiklander C, Cato A, Vinge E, Andersson A - Diabetes Care (2010)

Bottom Line: Determination of serum metformin with the LCMSMS technique is useful in patients on metformin treatment.Few patients had values >20 micromol/l.Metformin measurement is less suitable for dose titration.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology, University Hospital MAS, Malmö, Sweden. anders.frid@skane.se

ABSTRACT

Objective: To study trough levels of metformin in serum and its intra-individual variation in patients using a newly developed assay.

Research design and methods: Trough serum levels of metformin were measured once using liquid chromatography-tandem mass spectrometry (LCMSMS) in 137 type 2 diabetic patients with varying renal function (99 men) and followed repeatedly during 2 months in 20 patients (16 men) with estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) body surface.

Results: Patients with eGFR >60, 30-60, and <30 ml/min/1.73 m(2) had median trough metformin concentrations of 4.5 micromol/l (range 0.1-20.7, n = 107), 7.71 micromol/l (0.12-15.15, n = 21), and 8.88 micromol/l (5.99-18.60, n = 9), respectively. The median intra-individual overall coefficient of variation was 29.4% (range 9.8-74.2).

Conclusions: Determination of serum metformin with the LCMSMS technique is useful in patients on metformin treatment. Few patients had values >20 micromol/l. Metformin measurement is less suitable for dose titration.

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Box-plot of trough metformin levels in 137 patients grouped in patients with eGFR <30 ml/min/1.73 m2 (n = 9), 30–60 ml/min/1.73 m2, and >60 ml/min/1.73 m2 (n = 107). The outliers marked in the group with eGFR >60 ml/min/1.73 m2 are most likely due to patients accidentally taking their medication before the blood test.
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Figure 1: Box-plot of trough metformin levels in 137 patients grouped in patients with eGFR <30 ml/min/1.73 m2 (n = 9), 30–60 ml/min/1.73 m2, and >60 ml/min/1.73 m2 (n = 107). The outliers marked in the group with eGFR >60 ml/min/1.73 m2 are most likely due to patients accidentally taking their medication before the blood test.

Mentions: Of the 137 patients, 9 had an eGFR <30 ml/min/1.73 m2 and a median trough value of S-metformin at 8.88 μmol/l (range 5.99–18.60); 21 patients had an eGFR of 30–60 ml/min/1.73 m2 and a median S-metformin of 7.71 μmol/l (range 0.12–15.15); and 107 patients had an eGFR of >60 ml/min/1.73m2 and a median S-metformin of 4.5 μmol/l (range 0.1–20.7). The median doses of metformin were 1,500 mg (1,000–3,000), 1,500 mg (500–3,000), and 1,500 mg (500–3,000) for each group, respectively (Fig. 1).


Novel assay of metformin levels in patients with type 2 diabetes and varying levels of renal function: clinical recommendations.

Frid A, Sterner GN, Löndahl M, Wiklander C, Cato A, Vinge E, Andersson A - Diabetes Care (2010)

Box-plot of trough metformin levels in 137 patients grouped in patients with eGFR <30 ml/min/1.73 m2 (n = 9), 30–60 ml/min/1.73 m2, and >60 ml/min/1.73 m2 (n = 107). The outliers marked in the group with eGFR >60 ml/min/1.73 m2 are most likely due to patients accidentally taking their medication before the blood test.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2875440&req=5

Figure 1: Box-plot of trough metformin levels in 137 patients grouped in patients with eGFR <30 ml/min/1.73 m2 (n = 9), 30–60 ml/min/1.73 m2, and >60 ml/min/1.73 m2 (n = 107). The outliers marked in the group with eGFR >60 ml/min/1.73 m2 are most likely due to patients accidentally taking their medication before the blood test.
Mentions: Of the 137 patients, 9 had an eGFR <30 ml/min/1.73 m2 and a median trough value of S-metformin at 8.88 μmol/l (range 5.99–18.60); 21 patients had an eGFR of 30–60 ml/min/1.73 m2 and a median S-metformin of 7.71 μmol/l (range 0.12–15.15); and 107 patients had an eGFR of >60 ml/min/1.73m2 and a median S-metformin of 4.5 μmol/l (range 0.1–20.7). The median doses of metformin were 1,500 mg (1,000–3,000), 1,500 mg (500–3,000), and 1,500 mg (500–3,000) for each group, respectively (Fig. 1).

Bottom Line: Determination of serum metformin with the LCMSMS technique is useful in patients on metformin treatment.Few patients had values >20 micromol/l.Metformin measurement is less suitable for dose titration.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology, University Hospital MAS, Malmö, Sweden. anders.frid@skane.se

ABSTRACT

Objective: To study trough levels of metformin in serum and its intra-individual variation in patients using a newly developed assay.

Research design and methods: Trough serum levels of metformin were measured once using liquid chromatography-tandem mass spectrometry (LCMSMS) in 137 type 2 diabetic patients with varying renal function (99 men) and followed repeatedly during 2 months in 20 patients (16 men) with estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) body surface.

Results: Patients with eGFR >60, 30-60, and <30 ml/min/1.73 m(2) had median trough metformin concentrations of 4.5 micromol/l (range 0.1-20.7, n = 107), 7.71 micromol/l (0.12-15.15, n = 21), and 8.88 micromol/l (5.99-18.60, n = 9), respectively. The median intra-individual overall coefficient of variation was 29.4% (range 9.8-74.2).

Conclusions: Determination of serum metformin with the LCMSMS technique is useful in patients on metformin treatment. Few patients had values >20 micromol/l. Metformin measurement is less suitable for dose titration.

Show MeSH