Combining oral agents could reduce insulin need in gestational diabetes
medwireNews: Glyburide and metformin are comparable treatments for gestational diabetes, and their combination reduces the need for insulin after treatment failure, results of a randomized trial suggest.
“These results support the benefit of using an additional oral hypoglycemic agent in the case of a treatment failure before switching to insulin,” say Enav Yefet (Emek Medical Center, Afula, Israel) and colleagues.
The open-label trial involved women with gestational diabetes diagnosed at 13–33 weeks of gestation whose blood glucose was poorly controlled by diet alone. Participants were randomly assigned to receive either glyburide 2.5–20.0 mg per day or metformin 850–2550 mg per day.
The researchers found that treatment failure – defined as either poor glycemic control or treatment discontinuation due to adverse effects – occurred in 34% of 53 patients taking glyburide and 29% of 51 patients in the metformin group, a nonsignificant difference.
Of the 18 patients with glyburide treatment failure, six cases were attributed to adverse effects, whereas 12 had insufficient glycemic control. In the metformin group, however, only one of 15 patients experienced treatment failure due to adverse effects, while the remaining 14 had poor glycemic control.
The adverse event requiring medication discontinuation was hypoglycemia in patients receiving glyburide and gastrointestinal discomfort in those receiving metformin, with rates of 11% and 2%, respectively.
Following treatment failure with either glyburide or metformin, the other drug was added if optimal glycemic control was not achieved, and the drugs were switched in patients experiencing adverse events. This resulted in treatment success for 50% of patients initially assigned to glyburide, compared with 87% of patients initially assigned to metformin, a significant difference.
Finally, insulin was given if both oral agents failed after second-line treatment. A total of 17% of patients in the glyburide group went on to receive insulin treatment, compared with 4% in the metformin group.
Yefet and colleagues explain that combining the two oral drugs reduced the overall proportion of patients requiring insulin from 32% to 11%, “indicating that a protocol comprising two oral hypoglycemic agents as first- and second-line therapy is effective for glycemic control in 89% of patients.”
Mean daily, preprandial, and postprandial glucose measurements throughout the study were not significantly different in the glyburide and metformin groups (100.9 vs 101.3, 88.7 vs 91.3, and 115.3 vs 112.6 mg/dL, respectively), and maternal and neonatal outcomes were comparable, report the team in Diabetes Care.
And they conclude that insulin “should be reserved for patients who failed to respond to both oral treatments or who experienced adverse effects as a result of both.”
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