How should insulin glargine (Lantus) be dosed?

How to Dose Lantus (Insulin Glargine)

For type 2 diabetes patients not currently on insulin, start Lantus at 10 units once daily (or 0.2 units/kg), administered subcutaneously at the same time each day, and titrate by 2 units every 3 days until fasting blood glucose reaches target (<100 mg/dL). 1

Initial Dosing by Patient Type

Type 2 Diabetes (Insulin-Naïve)

• Starting dose: 10 units once daily OR 0.2 units/kg 1
• Administer at any consistent time of day (morning or bedtime equally effective) 2
• Continue metformin; consider discontinuing other oral agents 3

Type 1 Diabetes

• Starting dose: Approximately one-third of total daily insulin requirements 1
• Must combine with short-acting prandial insulin for remaining two-thirds 1
• Can be administered before breakfast, dinner, or bedtime with similar efficacy 4

Hospitalized Patients (Non-Critical Care)

Calculate total daily insulin dose based on blood glucose and patient characteristics 3:

• 0.2-0.3 units/kg/day for patients:

  • Age ≥70 years, OR
  • GFR <60 mL/min

• 0.4 units/kg/day for patients with blood glucose 140-200 mg/dL

• 0.5 units/kg/day for patients with blood glucose 201-400 mg/dL

Distribute as 50% basal insulin (Lantus) and 50% nutritional (prandial) insulin 3

Titration Strategy

Outpatient Titration

Standard algorithm 5, 6:

• Set fasting plasma glucose target (<100 mg/dL)
• Increase dose by 2 units every 3 days until target reached without hypoglycemia
• For hypoglycemia without clear cause, reduce dose by 10-20%

Alternative patient-managed titration 7:

• Increase by 2 units every 3 days if fasting blood glucose remains elevated
• Hold increase if blood glucose <72 mg/dL (<4.0 mmol/L)

Signs of Overbasalization

Consider adding prandial insulin or GLP-1 RA when 5:

• Basal dose exceeds ~0.5 units/kg/day
• Elevated bedtime-to-morning glucose differential
• Hypoglycemia (aware or unaware)
• High glucose variability

Converting from Other Insulins

From NPH Insulin

• Once-daily NPH → Once-daily Lantus: Use same dose 1
• Twice-daily NPH → Once-daily Lantus: Use 80% of total NPH dose 1
  • This dose reduction reduces hypoglycemia risk

Timing Flexibility

Lantus can be administered at any consistent time daily with equivalent efficacy 2, 4:

• Morning administration: Lower nocturnal hypoglycemia (59.5% vs 77.5% bedtime) 4
• Bedtime administration: Traditional timing, equally effective 2
• Before dinner: Intermediate option 4

Administration Technique

Critical Points

• Subcutaneous injection only - never intravenous or via insulin pump 1
• Rotate injection sites within same region (abdomen, thigh, deltoid) 1
• Inject at least 1 cm from previous injection sites 8
• Allow refrigerated insulin to reach room temperature (30-60 minutes) before injection 8
• Administer at 90-degree angle into subcutaneous tissue 8

Storage

• Unopened: Refrigerate at 2-8°C (36-46°F) 8
• Opened: Room temperature 15-30°C (59-86°F) for up to 28 days 8

Special Populations

Elderly or Renal Impairment

• Start conservatively at 0.2-0.3 units/kg/day 3
• Use insulin-sensitive correction scale 3
• Monitor closely for hypoglycemia

NPO/Fasting Patients

• Continue basal insulin alone 3
• Add correction doses with rapid-acting insulin every 4 hours 3
• Hold prandial insulin 3

Common Pitfalls to Avoid

Never use sliding-scale insulin alone - this triples hyperglycemia risk and provides inadequate control 3

Don't underdose - inadequate titration is the most common error; continue increasing dose every 3 days until fasting glucose reaches target 5, 7

Avoid therapeutic inertia - reassess and modify treatment every 3-6 months 5

Don't share insulin pens between patients - risk of blood-borne disease transmission 9