A patient on insulin glargine (Lantus) 20 units at bedtime has fasting glucose ~220 mg/dL each morning; how many additional units should the bedtime dose be increased?

Increase Lantus by 4 Units Every 3 Days Until Fasting Glucose Reaches Target

For a patient on Lantus 20 units at bedtime with persistent morning fasting glucose around 220 mg/dL, increase the dose by 4 units every 3 days until fasting glucose consistently reaches 80–130 mg/dL. 1

Immediate Dose Adjustment

• Increase Lantus from 20 units to 24 units tonight, then continue systematic titration every 3 days based on fasting glucose patterns 1
• The current dose of 20 units is profoundly inadequate for a fasting glucose of 220 mg/dL, requiring aggressive escalation 1

Evidence-Based Titration Algorithm

Standard Protocol

• Increase by 4 units every 3 days when fasting glucose is ≥180 mg/dL (as in this case with 220 mg/dL) 1
• Increase by 2 units every 3 days when fasting glucose is 140–179 mg/dL 1
• Target fasting glucose: 80–130 mg/dL 1

Expected Trajectory

• Starting at 20 units with fasting glucose 220 mg/dL, expect to reach approximately 32–40 units within 2–3 weeks of systematic titration 1, 2
• Each 4-unit increment typically lowers fasting glucose by approximately 30–50 mg/dL, though individual response varies 1

Daily Monitoring Requirements

• Check fasting glucose every morning during titration to guide dose adjustments 1, 3
• Record all fasting values to identify patterns over each 3-day period 1
• If any fasting glucose falls <70 mg/dL, immediately reduce the dose by 10–20% and treat with 15 g fast-acting carbohydrate 1

Critical Threshold: When to Stop Basal Escalation

• Cease further Lantus increases when the dose approaches 0.5–1.0 units/kg/day without achieving fasting glucose targets 1
• At this threshold, add prandial (mealtime) insulin rather than continuing basal escalation to avoid "over-basalization" 1
• Clinical signals requiring prandial insulin addition include:
  • Basal dose >0.5 units/kg/day
  • Bedtime-to-morning glucose differential ≥50 mg/dL
  • Episodes of hypoglycemia despite overall hyperglycemia
  • High glucose variability throughout the day 1

Timing Flexibility

• Lantus can be administered at bedtime, in the morning, or at any consistent time without significant difference in efficacy 4, 5, 6
• Morning administration may reduce nocturnal hypoglycemia risk compared to bedtime dosing 3, 5
• The key is consistency—administer at the same time each day 1, 3

Foundation Therapy Optimization

• Continue metformin at maximum tolerated dose (up to 2000–2550 mg daily) when intensifying Lantus, as this combination reduces total insulin requirements by 20–30% 1
• Metformin should never be discontinued when adding or intensifying insulin unless specifically contraindicated 1

Expected Clinical Outcomes

• With systematic 4-unit increments every 3 days, most patients achieve fasting glucose 80–130 mg/dL within 2–4 weeks 1, 2
• This aggressive titration approach yields HbA1c reductions of 1.5–2.0% over 3–6 months 1
• Properly implemented basal insulin titration does not increase hypoglycemia incidence when dose adjustments follow the protocol 1

Common Pitfalls to Avoid

• Do not delay dose escalation when fasting glucose consistently exceeds 180 mg/dL; prolonged hyperglycemia increases complication risk 1
• Do not use 2-unit increments for fasting glucose ≥180 mg/dL—this under-doses and prolongs time to target 1
• Do not continue escalating Lantus beyond 0.5–1.0 units/kg/day without addressing postprandial hyperglycemia with prandial insulin 1
• Never rely solely on correction (sliding-scale) insulin without adequate basal coverage; this reactive approach is condemned by major diabetes guidelines 1

Patient Self-Titration Empowerment

• Equip the patient with a self-titration algorithm to adjust their own Lantus dose based on fasting glucose readings 1, 2
• Patient-managed titration (increasing by 2 units every 3 days when fasting glucose remains above target) achieves greater HbA1c reductions than clinic-managed titration alone 2
• Provide clear written instructions: "If your average fasting glucose over 3 days is ≥180 mg/dL, increase your Lantus by 4 units; if 140–179 mg/dL, increase by 2 units" 1, 2