In gestational diabetes treated with metformin, not meeting blood glucose targets, what is the most appropriate next step?

• A. Increase metformin dose
• B. Add Insulin Lispro
• C. Switch to glyburide
• D. Add metformin and insulin glargine

Answer: (B)

When glucose targets aren’t reached with metformin in gestational diabetes, you escalate to insulin therapy to achieve tighter control. Metformin helps by reducing hepatic glucose production and improving insulin sensitivity, but it doesn’t provide the rapid, meal-time coverage that insulin offers. Adding a rapid-acting insulin taken with meals, such as lispro, directly tackles postprandial glucose rises while continuing metformin.

Raising the metformin dose is often limited by gastrointestinal tolerance and may not adequately address post-meal spikes. Switching to glyburide is generally less favored because insulin delivers proven fetal safety with reliable glucose control. Starting with a rapid-acting insulin to cover meals targets the most common remaining issue—postprandial hyperglycemia—whereas basal insulin alone may miss these spikes.