What is the recommended dosage and administration of Lantus (glargine insulin) for patients with diabetes?

Lantus (Insulin Glargine) Dosing and Administration

Initial Dosing Guidelines

For insulin-naive patients with type 2 diabetes, start Lantus at 10 units once daily or 0.1-0.2 units/kg body weight, administered at the same time each day. 1, 2, 3

Type 2 Diabetes Starting Doses

• Standard initiation: 10 units once daily for patients with mild-to-moderate hyperglycemia (A1C <9%) 1, 2
• Weight-based dosing: 0.1-0.2 units/kg/day is the recommended range, with higher doses (0.2 units/kg) used for more severe hyperglycemia 1, 2, 3
• Severe hyperglycemia (A1C ≥9%, blood glucose ≥300-350 mg/dL, or symptomatic/catabolic features): Consider starting with basal-bolus insulin immediately at 0.3-0.5 units/kg/day total daily dose, split between basal and prandial insulin 1, 2
• Continue metformin unless contraindicated when initiating basal insulin, and possibly one additional non-insulin agent 1, 2

Type 1 Diabetes Starting Doses

• Total daily insulin requirement: 0.4-1.0 units/kg/day, with 0.5 units/kg/day typical for metabolically stable patients 1, 2
• Basal-bolus split: Approximately one-third of total daily insulin as Lantus (basal), with the remainder as short-acting prandial insulin 3
• Alternatively, use 40-60% of total daily dose as basal insulin and 40-60% as prandial insulin divided among meals 1, 2
• Must be used with short-acting insulin at mealtimes in type 1 diabetes 4, 3

Dose Titration Algorithm

Increase Lantus by 2-4 units every 3 days until fasting blood glucose reaches 80-130 mg/dL. 1, 2

Specific Titration Steps

• If fasting glucose 140-179 mg/dL: Increase by 2 units every 3 days 1, 2
• If fasting glucose ≥180 mg/dL: Increase by 4 units every 3 days 1, 2
• If hypoglycemia occurs: Reduce dose by 10-20% immediately 1, 2
• If more than 2 fasting glucose values per week are <80 mg/dL: Decrease dose by 2 units 1
• Daily fasting blood glucose monitoring is essential during titration 1, 2

Administration Guidelines

Administer Lantus subcutaneously once daily at the same time each day, rotating injection sites within the same region. 1, 3

Key Administration Points

• Injection sites: Abdominal area, thigh, or deltoid 3
• Rotate sites within the same region to reduce risk of lipodystrophy and localized cutaneous amyloidosis 3
• Do not inject into areas of lipodystrophy or localized cutaneous amyloidosis 3
• Timing flexibility: Can be given at any time of day (morning, dinner, or bedtime) but must be consistent 1, 5
• Do not dilute or mix with any other insulin or solution due to its low pH 1, 3
• Do not administer intravenously or via insulin pump 3

Critical Threshold: When to Stop Escalating Basal Insulin

When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add prandial insulin rather than continuing to escalate basal insulin alone. 1, 2

Signs of "Overbasalization"

• Basal insulin dose >0.5 units/kg/day 1
• Bedtime-to-morning glucose differential ≥50 mg/dL 1
• Hypoglycemia episodes 1
• High glucose variability 1
• Fasting glucose controlled but A1C remains elevated 1, 2

Adding Prandial Insulin

• Start with 4 units of rapid-acting insulin before the largest meal, or use 10% of current basal dose 1, 2
• Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on postprandial glucose readings 1
• Alternative: Consider adding a GLP-1 receptor agonist to basal insulin for postprandial control with less weight gain and hypoglycemia risk 1, 2

Pharmacological Properties

Lantus has a peakless profile with onset of action at approximately 1 hour and duration of up to 24 hours. 4, 1

Clinical Advantages

• More consistent absorption than NPH insulin 4, 1
• Reduced hypoglycemia risk, especially nocturnal hypoglycemia, compared to NPH insulin 4, 1, 6, 7
• Peakless profile provides more stable glycemic control throughout 24 hours 4, 1, 7
• Once-daily dosing is standard, though twice-daily may be needed in some patients 1, 8

Special Dosing Considerations

Twice-Daily Dosing Indications

• Consider splitting dose when once-daily administration fails to provide 24-hour coverage 1
• Particularly useful in type 1 diabetes with high glycemic variability 1
• Patients with persistent nocturnal hypoglycemia with morning hyperglycemia 1
• High absolute doses that may exceed absorption capacity for once-daily administration 1

High-Risk Populations Requiring Lower Doses

• Elderly patients (>65 years): Start with 0.1-0.25 units/kg/day 1, 2
• Renal failure: Use lower doses (0.1-0.25 units/kg/day) 1, 2
• Poor oral intake: Reduce to 0.1-0.25 units/kg/day 1, 2
• Hospitalized patients on high-dose home insulin (≥0.6 units/kg/day): Reduce total daily dose by 20% upon admission 1, 2

Special Clinical Situations

• Puberty: Requirements may increase to 1.5 units/kg/day due to hormonal influences 1
• Pregnancy and medical illness: Higher doses may be needed 1
• Perioperative period: Reduce dose by approximately 25% the evening before surgery 1
• Patients on steroids: Increase prandial and correction insulin by 40-60% in addition to basal insulin 1

Switching from Other Insulins

From NPH Insulin

• Once-daily NPH to once-daily Lantus: Use the same dose 3
• Twice-daily NPH to once-daily Lantus: Use 80% of total NPH dose 3, 9

From Toujeo (U-300 Glargine)

• From once-daily Toujeo to once-daily Lantus: Use 80% of Toujeo dose 3

Common Pitfalls to Avoid

• Do not delay insulin initiation in patients not achieving glycemic goals with oral medications 1, 2
• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia—this leads to overbasalization with increased hypoglycemia risk 1, 2
• Do not use Lantus to treat postprandial hyperglycemia—this requires prandial insulin 1, 6
• Do not mix or dilute Lantus with other insulins or solutions 1, 3
• Do not abruptly discontinue metformin when starting insulin—continue unless contraindicated 1, 2
• Do not wait longer than 3 days between basal insulin adjustments in stable patients 1

Monitoring Requirements

• Daily fasting blood glucose monitoring during titration phase 1, 2
• Assess insulin dose adequacy at every clinical visit 1, 2
• Check A1C every 3 months during intensive titration 1
• Monitor for signs of overbasalization at each assessment 1
• Increase monitoring frequency during any insulin regimen changes 3