Glibenclamide - what it is and how it works
Glibenclamide is an oral medication in the form of a tablet. It works by stimulating the beta cells in the pancreas that produce insulin, causing them to produce more insulin. It is a sulphonylurea drug which means it can cause hypoglycaemia or hypos (blood sugar levels under 4.0mmol/L) and so you should carry a hypo kit if you take this drug.
Not routinely used in the UK
This medication is not routinely used for the treatment of gestational diabetes, however it is sometimes used for people who have severe needle phobia and yet cannot control their levels with Metformin and dietary changes alone. It is also sometimes offered in addition to insulin in those with high insulin resistance. It does not cross the placenta in large amounts.
Since starting our Facebook support group in 2014, with over 2,000 through out that time, we have only seen 2 members be prescribed this drug for help with controlling blood sugar levels.
Things to consider
Although it can be used to help increase insulin production and will assist in managing blood sugar levels, in research, Metformin and insulin are shown to have a better effect in gestational diabetes on fetal growth, birth weight and neonatal hypoglycaemia following birth. There are currently no studies of the long term effects of this drug on the offspring of babies born to mothers with gestational diabetes.
1.2.25 Consider glibenclamide for women with gestational diabetes:
- in whom blood glucose targets are not achieved with metformin but who decline insulin therapy or
- who cannot tolerate metformin. [new 2015]
Glibenclamide, metformin, and insulin for the treatment of gestational diabetes: a systematic review and meta-analysis
Conclusions At short term, in women with gestational diabetes requiring drug treatment, glibenclamide is clearly inferior to both insulin and metformin, while metformin (plus insulin when required) performs slightly better than insulin. According to these results, glibenclamide should not be used for the treatment of women with gestational diabetes if insulin or metformin is available.
Gestational diabetes mellitus - Emerging treatments, BMJ Best Practice
Glibenclamide, which does not cross the placenta in large amounts, was compared with insulin therapy in a randomised study of pregnancies complicated by GDM; this study of 404 patients showed comparable outcomes with both treatments.  One systematic review comparing outcomes of GDM treated with oral antihyperglycaemic agents versus insulin found that glibenclamide and insulin therapy yielded similar outcomes. However, another systematic review found that, compared with insulin, glibenclamide was associated with a non-statistically significant 93 g higher birth weight.  A randomised trial comparing the perinatal impacts of glibenclamide and metformin in the treatment of pregnant women with GDM who required adjunctive therapy to diet and physical activity found that neonatal blood glucose levels were lower with glibenclamide, while newborn weight and the ponderal index (birth weight/height^3×100) were lower with metformin.  There are no studies that assess the long-term impact of glibenclamide exposure on offspring outcomes.
The effectiveness of glibenclamide in women with gestational diabetes.
CONCLUSION: The use of glibenclamide in pregnancy is associated with adequate glycaemic control in 77% of women and achieved similar foetal outcomes to women treated with insulin.