A Feasibility Study Looking at the Use of Glibenclamide and metfoRmin Versus stAndard Care in gEstational diabeteS

A Feasibility Study Looking at the Use of Glibenclamide and metfoRmin Versus stAndard Care in gEstational diabeteS

The aim of this open label feasibility study is to determine recruitment rates to a randomised trial of glibenclamide compared with insulin (both in addition to maximum tolerated metformin) for the treatment of Gestational Diabetes Mellitus (GDM). This feasibility trial will inform the design of a future substantive multicentre trial to test the hypothesis that combination therapy with glibenclamide and metformin could reduce the number of pregnant women with GDM who require insulin and would be superior to metformin and insulin in terms of acceptability and cost effectiveness.

Women with GDM who have "failed" monotherapy with metformin will be recruited and randomised to either receive glibenclamide (test arm) or standard care with insulin, both in addition to their maximum tolerated dose of metformin. Patients will be recruited from three of the antenatal clinics.

This is a feasibility study in preparation for a large multicentre randomised trial to test the hypothesis that the addition of glibenclamide to metformin (combination therapy) could reduce the number of pregnant women with gestational diabetes mellitus requiring insulin, without compromising glycaemic control or other clinical outcomes. The investigators hypothesise that combination therapy with metformin and glibenclamide is likely to be preferable to metformin and insulin in terms of acceptability and cost.

Inclusion Criteria:

• Pregnant women diagnosed with gestational diabetes who fail to achieve "adequate glycaemic control" on maximum tolerated dose metformin
• Inadequate glycaemic control is defined according to the SIGN 116 guidelines.

Exclusion Criteria:

• Pregnant women requiring insulin prior to 20 weeks gestation or after 36 weeks gestation.
• Pregnant women not taking at least 500mg metformin daily.
• Patients with suspected Type 1 diabetes mellitus presenting in pregnancy.
• Women with allergies to either glibenclamide or insulin or any of their excipients.
• Women with any contraindications to sulfonylurea therapy.
• Women unable to give informed consent.