Lantus (Insulin Glargine) Dosing and Titration Guidelines
Starting Dose Recommendations
For adults with type 2 diabetes who are insulin-naïve, start Lantus at 10 units once daily or 0.1–0.2 units/kg/day, administered at the same time each day. 1, 2 For patients with more severe hyperglycemia (HbA1c ≥9% or fasting glucose ≥300 mg/dL), consider higher starting doses of 0.3–0.4 units/kg/day as part of a basal-bolus regimen from the outset. 1
For adults with type 1 diabetes, the recommended starting dose is approximately one-third of the total daily insulin requirement (typically 0.4–1.0 units/kg/day total, with 0.5 units/kg/day as a standard starting point). 1, 3, 2 The remaining two-thirds should be provided as rapid-acting prandial insulin divided among meals. 1, 3
Continue metformin (unless contraindicated) and possibly one additional non-insulin agent when initiating Lantus in type 2 diabetes, as this combination reduces total insulin requirements by 20–30% and provides superior glycemic control. 1, 4
Systematic Titration Protocol
Basal Insulin Adjustment Algorithm
- Increase Lantus by 2 units every 3 days if fasting glucose is 140–179 mg/dL 1
- Increase Lantus by 4 units every 3 days if fasting glucose is ≥180 mg/dL 1
- Target fasting glucose: 80–130 mg/dL 5, 1
- If hypoglycemia (<70 mg/dL) occurs without clear cause, reduce the dose by 10–20% immediately 1
Daily fasting glucose monitoring is essential during the titration phase to guide dose adjustments. 1 Patients can be taught self-titration using these algorithms, which improves glycemic management. 5
Critical Threshold: Recognizing "Over-Basalization"
When basal insulin approaches 0.5–1.0 units/kg/day without achieving glycemic targets, stop escalating Lantus and add prandial insulin or a GLP-1 receptor agonist instead. 5, 1, 4 Continuing to increase basal insulin beyond this threshold leads to "over-basalization"—a dangerous pattern characterized by:
- Basal dose >0.5 units/kg/day 5, 1
- Bedtime-to-morning glucose differential ≥50 mg/dL 1
- Episodes of hypoglycemia 1
- High glucose variability 1
This threshold exists because further basal escalation produces diminishing returns with increased hypoglycemia risk rather than improved control. 1
Adding Prandial Insulin Coverage
When basal insulin has been optimized (fasting glucose 80–130 mg/dL) but HbA1c remains above target after 3–6 months, or when basal insulin exceeds 0.5 units/kg/day, add prandial insulin. 5, 1
- Start with 4 units of rapid-acting insulin before the largest meal 1
- Alternatively, use 10% of the current basal dose 1
- Administer 0–15 minutes before meals 1
- Titrate each meal dose by 1–2 units (or 10–15%) every 3 days based on 2-hour postprandial glucose 1
- Target postprandial glucose <180 mg/dL 1
Consider adding a GLP-1 receptor agonist to basal insulin before advancing to prandial insulin, as this combination provides comparable HbA1c reduction with less hypoglycemia and weight gain. 5, 1
Administration Guidelines
- Administer Lantus subcutaneously once daily at the same time every day (morning, evening, or bedtime—consistency matters more than specific timing) 1, 4, 2
- Inject into the abdominal area, thigh, or deltoid, rotating sites within the same region to reduce lipodystrophy risk 2
- Do not dilute or mix Lantus with any other insulin or solution due to its acidic pH 1, 2
- Do not administer intravenously or via an insulin pump 2
- Visually inspect for particulate matter or discoloration; use only if clear and colorless 2
Special Populations and Situations
High-Risk Patients (Elderly, Renal Impairment, Poor Oral Intake)
Start with lower doses of 0.1–0.25 units/kg/day to minimize hypoglycemia risk. 1 For hospitalized patients on high-dose home insulin (≥0.6 units/kg/day), reduce the total daily dose by 20% upon admission. 1
Chronic Kidney Disease
For CKD stage 5, reduce total daily insulin by 50% for type 2 diabetes and 35–40% for type 1 diabetes. 1
Pregnancy and Puberty
Higher doses are required during puberty (potentially up to 1.5 units/kg/day), pregnancy, and acute illness. 1, 4
Switching from Other Insulins
- From NPH once daily: Use the same dose 2
- From NPH twice daily: Use 80% of the total NPH dose 2
- From Toujeo (U-300 glargine): Use 80% of the Toujeo dose 2
Hypoglycemia Management
- Treat glucose <70 mg/dL immediately with 15 grams of fast-acting carbohydrate 1
- Recheck in 15 minutes and repeat if needed 1
- Reduce the implicated insulin dose by 10–20% if hypoglycemia occurs without obvious cause 1
- If more than two fasting glucose values per week are <80 mg/dL, decrease Lantus by 2 units 1
Common Pitfalls to Avoid
- Never delay insulin initiation in patients not achieving glycemic goals with oral medications—this prolongs hyperglycemia exposure and increases complication risk 1
- Never discontinue metformin when starting insulin unless contraindicated, as this leads to higher insulin requirements and more weight gain 1
- Never continue escalating Lantus beyond 0.5–1.0 units/kg/day without addressing postprandial hyperglycemia—this causes over-basalization with increased hypoglycemia and suboptimal control 5, 1
- Never use sliding-scale insulin as monotherapy—major diabetes guidelines condemn this approach as ineffective and unsafe 1
- Never give rapid-acting insulin at bedtime as a sole correction dose—this markedly raises nocturnal hypoglycemia risk 1
Expected Clinical Outcomes
With properly implemented basal insulin therapy using Lantus:
- Equivalent or better glycemic control compared to NPH insulin with significantly lower rates of nocturnal hypoglycemia 6, 7, 8
- 46% reduction in severe hypoglycemia risk and 59% reduction in severe nocturnal hypoglycemia compared to NPH 7
- HbA1c reduction of 1.5–2.0% when added to metformin in type 2 diabetes 1
- Improved treatment satisfaction due to once-daily dosing and reduced hypoglycemia 6, 8
The peakless, 24-hour action profile of Lantus provides more stable basal coverage than NPH insulin, with a smooth time-action curve and no pronounced peaks. 6, 9, 8, 10