How should I adjust basal and bolus insulin and consider adjunct therapy to control post‑prandial glucose spikes to ~300 mg/dL in a patient on morning insulin glargine (Lantus) 18 U, rapid‑acting insulin (Lipton) 4–6 U before meals, and dapagliflozin (Farxiga) 25 mg, with fasting glucose averaging 106 mg/dL and symptomatic hypoglycemia when <100 mg/dL?

Aggressive Insulin Intensification Required for Severe Post‑Prandial Hyperglycemia

Your patient needs immediate addition of prandial insulin before meals—the current regimen of basal insulin alone is completely inadequate for glucose spikes to 300 mg/dL, and continuing to escalate Lantus beyond 18 units without addressing meal‑time coverage will only increase hypoglycemia risk without controlling post‑prandial excursions. 1

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Critical Problem: Basal Insulin Alone Cannot Control Post‑Prandial Spikes

• Lantus (basal insulin) suppresses hepatic glucose production between meals but does not address the carbohydrate load from food—your patient's 300 mg/dL spikes after meals demonstrate complete lack of prandial coverage. 1, 2
• The American Diabetes Association explicitly states that when fasting glucose is controlled (106 mg/dL average) but post‑prandial excursions exceed 180 mg/dL, prandial insulin must be added rather than further basal escalation. 1, 2
• Continuing to increase Lantus beyond the current 18 units (approximately 0.3 units/kg for a typical adult) will cause hypoglycemia between meals while failing to control meal‑time spikes—this is called "over‑basalization." 1

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Immediate Medication Adjustments

1. Add Rapid‑Acting Insulin Before Meals

• Start with 4–6 units of rapid‑acting insulin (lispro, aspart, or glulisine) before each of the three largest meals to provide prandial coverage. 1, 2
• Administer the rapid‑acting insulin 0–15 minutes before meals for optimal post‑prandial control. 1
• Target post‑prandial glucose <180 mg/dL measured 1–2 hours after the start of meals. 2

2. Titrate Prandial Insulin Aggressively

• Increase each meal dose by 2 units every 3 days if the 2‑hour post‑prandial glucose consistently exceeds 180 mg/dL. 1, 2
• For glucose spikes to 300 mg/dL, you will likely need 10–15 units per meal within several weeks of titration. 1

3. Maintain or Modestly Increase Basal Insulin

• Keep Lantus at 18 units once daily (or increase to 20–22 units if fasting glucose drifts above 130 mg/dL). 1, 3
• Do not escalate Lantus beyond 0.5 units/kg/day (approximately 35–40 units for a 70 kg adult) without concurrent prandial insulin, as this causes hypoglycemia without improving post‑prandial control. 1

4. Optimize Farxiga (Dapagliflozin) Dosing

• Continue Farxiga 25 mg daily—this SGLT2 inhibitor provides complementary glucose lowering by increasing urinary glucose excretion and may reduce total insulin requirements by 10–20%. 4
• Farxiga stabilizes insulin dosing and mitigates insulin‑associated weight gain over 104 weeks in patients on high‑dose insulin. 4

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Alternative Strategy: GLP‑1 Receptor Agonist Instead of Prandial Insulin

• If the patient is unwilling or unable to inject insulin before every meal, consider adding a GLP‑1 receptor agonist (e.g., semaglutide, dulaglutide, liraglutide) to basal insulin as an alternative to prandial insulin. 1, 2
• GLP‑1 receptor agonists blunt post‑prandial glucose excursions through delayed gastric emptying and enhanced insulin secretion, providing comparable HbA1c reduction with lower hypoglycemia risk and weight loss rather than weight gain. 1, 2
• Fixed‑ratio combination products (IDegLira or iGlarLixi) are available for patients on both GLP‑1 RA and basal insulin. 2

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Addressing Symptomatic Hypoglycemia Below 100 mg/dL

• Your patient's symptoms when glucose falls below 100 mg/dL suggest hypoglycemia unawareness or an inappropriately high glycemic threshold—this is not true hypoglycemia (which occurs <70 mg/dL). 1, 5
• Do not raise the fasting glucose target above 100–130 mg/dL to accommodate these symptoms, as this will worsen long‑term glycemic control. 1, 3
• Instead, educate the patient that symptoms at 90–100 mg/dL are not dangerous and will resolve with consistent glucose control—recurrent hypoglycemia shifts glycemic thresholds lower, making future episodes harder to detect. 1, 5
• Treat only confirmed hypoglycemia <70 mg/dL with 15 grams of fast‑acting carbohydrate, recheck in 15 minutes, and repeat if needed. 1, 3

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Monitoring Requirements During Intensification

• Check fasting glucose daily to guide Lantus adjustments (target 80–130 mg/dL). 1, 3
• Measure glucose 1–2 hours after the start of each meal to assess prandial insulin adequacy (target <180 mg/dL). 1, 2
• Reassess HbA1c every 3 months during intensive titration to evaluate overall glycemic control. 1, 2

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Expected Clinical Outcomes

• With properly implemented basal‑bolus therapy, approximately 68% of patients achieve mean glucose <140 mg/dL versus only 38% with inadequate basal‑only regimens. 1
• HbA1c reduction of 1.5–2.5% is achievable within 3–6 months with aggressive prandial insulin titration. 1
• Correctly executed basal‑bolus regimens do not increase overall hypoglycemia incidence compared with inadequate basal‑only approaches. 1

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Critical Pitfalls to Avoid

• Do not continue escalating Lantus beyond 0.5 units/kg/day (approximately 35–40 units) without addressing post‑prandial hyperglycemia—this leads to hypoglycemia between meals while failing to control meal‑time spikes. 1, 2
• Do not administer rapid‑acting insulin at bedtime as a sole correction dose, as this markedly increases nocturnal hypoglycemia risk. 1
• Do not discontinue Farxiga when adding prandial insulin—SGLT2 inhibitors provide complementary glucose lowering and reduce insulin requirements. 4
• Do not delay adding prandial insulin when post‑prandial glucose consistently exceeds 250–300 mg/dL—this clearly indicates the need for meal‑time coverage. 1, 2