What is the maximum daily dose of insulin glargine (insulin glargine)?

Maximum Daily Dose of Insulin Glargine

There is no absolute maximum daily dose of insulin glargine—dosing should be titrated based on glycemic targets, with typical requirements ranging from 0.4-1.0 units/kg/day in type 1 diabetes and often ≥1 unit/kg/day in type 2 diabetes due to insulin resistance. 1

Typical Dosing Ranges

For Type 1 Diabetes:

• Total daily insulin requirements typically range from 0.4-1.0 units/kg/day, with basal insulin (including glargine) comprising 40-60% of the total daily dose 1
• During puberty, insulin requirements may increase dramatically to as much as 1.5 units/kg per day due to hormonal influences of growth hormone and sex hormone secretion 2

For Type 2 Diabetes:

• Patients generally require higher daily doses (approximately ≥1 unit/kg/day) compared to those with type 1 diabetes due to insulin resistance 1
• Starting doses for insulin-naive patients typically begin at 10 units daily or 0.1-0.2 units/kg/day 1

When High Doses Signal Need for Treatment Modification

Critical threshold for reassessment:

• If basal insulin dose exceeds 0.5 units/kg/day and A1C remains above target, advance to combination injectable therapy with GLP-1 receptor agonists or add prandial insulin rather than continuing to escalate glargine alone 1
• Clinical signals suggesting overbasalization include basal dose greater than 0.5 units/kg, high bedtime-morning glucose differential, hypoglycemia, and high variability 3

Special Considerations for Very High Doses

Concentrated formulations for patients requiring large volumes:

• U-500 regular insulin is indicated specifically for patients requiring >200 units of insulin per day 1
• U-300 glargine (Toujeo) allows higher doses per volume but has modestly lower efficacy per unit, requiring approximately 10-18% higher daily doses compared to U-100 glargine 1, 3
• For insulin-resistant patients requiring large doses, concentrated formulations may be more convenient (fewer injections) and comfortable (less volume to inject) 3

Practical Dosing Approach

Titration strategy:

• Increase dose by 10-15% or 2-4 units once or twice weekly until fasting blood glucose target is met 1
• Base titration on home glucose monitoring or A1C levels 1

When glargine may not provide 24-hour coverage:

• In some patients, glargine may not last 24 hours, and dividing the dose into two daily injections should be considered 2
• Insulin detemir and insulin glargine may require twice-daily dosing when once-daily administration fails to provide 24-hour coverage 1

Common Pitfalls to Avoid

Overbasalization:

• When basal insulin is optimally titrated to acceptable fasting glucose but A1C remains elevated, add prandial insulin or GLP-1 receptor agonist rather than continuing to escalate basal insulin 1
• The combination of basal insulin plus GLP-1 RA provides potent glucose-lowering with less weight gain and hypoglycemia compared to intensified insulin regimens alone 1

Special populations requiring dose adjustments:

• Elderly hospitalized patients with reduced oral intake should start with reduced total daily dose of 0.1-0.15 units/kg/day, given mainly as basal insulin 2
• Higher doses may be needed during puberty, pregnancy, and medical illness 1