How many units should the insulin glargine (Lantus) dose be increased in a 42‑year‑old woman with type 2 diabetes, HbA1c 6.7 %, currently taking dapagliflozin (Farxiga) 10 mg daily, metformin 1000 mg twice daily, and insulin glargine 10 units nightly?

Increase Lantus by 2–4 Units Every 3 Days Until Fasting Glucose Reaches 80–130 mg/dL

For this 42‑year‑old woman with an HbA1c of 6.7% on dapagliflozin 10 mg, metformin 1000 mg BID, and Lantus 10 units, increase the basal insulin dose by 2 units every 3 days if fasting glucose is 140–179 mg/dL, or by 4 units every 3 days if fasting glucose is ≥180 mg/dL, targeting a fasting range of 80–130 mg/dL. 1

Current Regimen Assessment

• The patient's HbA1c of 6.7% is already at or near the ADA target of <7% for most adults with type 2 diabetes, indicating that aggressive insulin escalation may not be necessary and could increase hypoglycemia risk. 2
• Dapagliflozin 10 mg daily provides complementary glucose‑lowering through increased urinary glucose excretion (approximately 52–85 g/day), independent of insulin action, and contributes an additional 0.5–0.9% HbA1c reduction when added to metformin. 3, 4
• Metformin 1000 mg BID (2000 mg total daily) is at the recommended dose for combination therapy with insulin, reducing total insulin requirements by 20–30% and providing superior glycemic control compared with insulin alone. 1

Evidence‑Based Titration Protocol

• If fasting glucose is 140–179 mg/dL: Increase Lantus by 2 units every 3 days. 1
• If fasting glucose is ≥180 mg/dL: Increase Lantus by 4 units every 3 days. 1
• Target fasting glucose: 80–130 mg/dL. 1
• If unexplained hypoglycemia (<70 mg/dL) occurs: Immediately reduce the Lantus dose by 10–20%. 1

Daily Monitoring Requirements

• Check fasting blood glucose every morning during the titration phase to guide dose adjustments every 3 days. 1
• If more than two fasting glucose values per week fall below 80 mg/dL, decrease the basal dose by 2 units to prevent hypoglycemia. 1, 5

Critical Threshold: When to Stop Escalating Basal Insulin

• When the Lantus dose approaches 0.5 units/kg/day (approximately 21–35 units for most adults) without achieving glycemic targets, stop further basal escalation and consider adding prandial insulin or a GLP‑1 receptor agonist rather than continuing to increase basal insulin alone. 2, 1
• Clinical signals of "over‑basalization" that warrant stopping basal escalation include: basal dose >0.5 units/kg/day, bedtime‑to‑morning glucose differential ≥50 mg/dL, any hypoglycemia episodes, or high glucose variability. 2, 1

Role of Dapagliflozin in This Regimen

• Dapagliflozin improves 24‑hour mean glucose by approximately 18 mg/dL and increases time spent in target glucose range (70–180 mg/dL) from 53% to 70% when added to metformin or insulin. 3
• The combination of dapagliflozin with basal insulin provides complementary mechanisms: insulin suppresses hepatic glucose production while dapagliflozin promotes urinary glucose excretion, resulting in improved glycemic control with minimal hypoglycemia risk. 3, 6
• Dapagliflozin facilitates weight loss of approximately 1.3–2.0 kg through urinary loss of 200–300 kcal/day, counteracting the weight gain typically associated with insulin intensification. 4, 7

Safety Considerations and Common Pitfalls

• Do not delay insulin titration when fasting glucose consistently exceeds 130 mg/dL, as prolonged hyperglycemia increases complication risk. 1
• Do not discontinue metformin when intensifying insulin therapy unless contraindicated, as this leads to higher insulin requirements and greater weight gain. 1
• Do not continue escalating Lantus beyond 0.5–1.0 units/kg/day without addressing postprandial hyperglycemia, as this causes over‑basalization with increased hypoglycemia risk and suboptimal control. 2, 1
• Monitor for genital infections (more common with dapagliflozin) and ensure adequate hydration to minimize urinary tract infection risk. 6, 8

Expected Clinical Outcomes

• With systematic basal insulin titration combined with dapagliflozin and metformin, expect fasting glucose to reach 80–130 mg/dL within 3–6 weeks of active titration. 1, 3
• The triple combination of metformin, dapagliflozin, and optimized basal insulin provides additive glucose‑lowering effects while minimizing hypoglycemia risk and facilitating modest weight loss. 3, 6, 7