Metformin May Edge Glyburide in Gestational Diabetes

By David Douglas

April 06, 2015

NEW YORK (Reuters Health) - Both metformin and glyburide are effective oral agents for maintaining glycemic control in gestational diabetes mellitus (GDM). However, certain side effects are greater with glyburide, according to Chinese researchers.

As Dr. Zhong-ning Zhu told Reuters Health by email, "glyburide was associated with higher maternal weight gain, higher neonatal birth weight, increased incidence of neonatal hypoglycemia, and increased incidence of macrosomia than metformin."

Dr. Zhu, of Hebei Medical University in Shijiazhuang, and colleagues did a network meta-analysis involving 18 randomized trials comparing oral agents or oral agents versus insulin. The number of patients enrolled ranged from around two dozen to more than 700, the researchers report in the Journal of Clinical Endocrinology & Metabolism, online March 24.

"There was no significant difference in maternal fasting blood glucose or HbAlc levels in GDM patients treated with insulin, metformin, and glyburide," Dr. Zhu said.

However, compared to insulin, metformin was associated with a lower weighted mean difference in maternal weight gain (-1.49 kg). This was also the case for gestational age (-0.16 weeks), but there was an increased incidence of premature birth (odds ratio, 1.63). All of the differences were statistically significant.

Use of glyburide was associated with a significant increases in neonatal birth weight (131 g), incidence of neonatal hypoglycemia (OR, 2.64) and an incidence of macrosomia (OR, 3.09).

Dr. Zhu and colleagues note that, "While no long term harms to the exposed offspring from either of these drugs have been demonstrated, no long-term studies have been performed with appropriate controls either in humans or animal models."

Another possible concern, they conclude, is that use of oral antidiabetic drugs alone may be insufficient, so clinicians "should counsel their patients on the risk of failure to achieve optimal glycemic control when used as a single agent."

Recently, a large Swedish study found that glyburide for GDM was associated with greater risk of harm than insulin in newborns. (See Reuters Health report March 30, 2015).


J Clin Endocrinol Metab 2015.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.