What is the recommended dosing and administration of insulin glargine (insulin glargine) for patients with type 1 or type 2 diabetes?

Insulin Glargine Dosing and Administration

Initial Dosing

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

Type 1 Diabetes

• Start with approximately one-third of total daily insulin requirements as insulin glargine (basal), with the remaining two-thirds provided as short-acting premeal insulin 1, 2
• Total daily insulin requirements typically range from 0.4-1.0 units/kg/day, with 0.5 units/kg/day being typical for metabolically stable patients 2, 3
• Basal insulin (glargine) should comprise 40-60% of total daily dose in patients on multiple daily injection regimens 2

Type 2 Diabetes

• Standard initiation: 10 units once daily or 0.1-0.2 units/kg/day 1, 2, 3
• Continue metformin unless contraindicated, and possibly one additional non-insulin agent 2, 3
• For severe hyperglycemia (A1C ≥9%, blood glucose ≥300-350 mg/dL, or symptomatic/catabolic features), consider higher starting doses of 0.3-0.5 units/kg/day as part of a basal-bolus regimen 2, 3

Administration Guidelines

Administer subcutaneously once daily at any time of day, but at the same time every day. 1, 2

• Inject into the abdominal area, thigh, or deltoid 1
• Rotate injection sites within the same region to reduce risk of lipodystrophy and localized cutaneous amyloidosis 1
• Do not administer intravenously or via an insulin pump 1
• Do not dilute or mix with any other insulin or solution 1, 2
• Visually inspect for particulate matter and discoloration; only use if clear and colorless 1

Dose Titration

Increase by 2-4 units (or 10-15%) once or twice weekly until fasting blood glucose reaches target of 80-130 mg/dL. 2, 3

Evidence-Based Titration Algorithm

• If fasting glucose is 140-179 mg/dL: increase by 2 units every 3 days 2, 3
• If fasting glucose is ≥180 mg/dL: increase by 4 units every 3 days 2, 3
• If more than 2 fasting glucose values per week are <80 mg/dL: decrease by 2 units 2, 3
• If hypoglycemia occurs without clear cause: reduce dose by 10-20% immediately 2, 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. 2, 3

Clinical Signals of Overbasalization

• Basal insulin dose >0.5 units/kg/day 2
• Bedtime-to-morning glucose differential ≥50 mg/dL 2
• Hypoglycemia episodes 2
• High glucose variability 2

Adding Prandial Insulin

• Start with 4 units of rapid-acting insulin before the largest meal, or 10% of current basal dose 2, 3
• Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on postprandial glucose readings 2

Special Populations and Situations

Hospitalized Patients

• For insulin-naive or low-dose insulin patients: start with 0.3-0.5 units/kg/day total daily dose, with half as basal insulin 2
• For patients on high-dose home insulin (≥0.6 units/kg/day): reduce total daily dose by 20% to prevent hypoglycemia 2
• Elderly patients (>65 years), those with renal failure, or poor oral intake: use lower doses of 0.1-0.25 units/kg/day 2

Switching from Other Insulins

• From once-daily NPH: use the same dose 1
• From twice-daily NPH: use 80% of total NPH dose 1
• From TOUJEO (U-300 glargine): use 80% of TOUJEO dose 1

Twice-Daily Dosing Considerations

Insulin glargine may require twice-daily dosing when once-daily administration fails to provide 24-hour coverage. 2

• Consider for type 1 diabetes patients with persistent glycemic variability 2
• Consider for patients requiring high basal insulin doses 2
• Consider for patients with refractory hypoglycemia despite appropriate once-daily dose titration 2

Pharmacokinetic Profile

• Onset of action: approximately 1 hour 4, 5
• Peak: no pronounced peak (peakless profile) 4, 5, 6
• Duration: approximately 24 hours 4, 5, 6
• This peakless profile provides relatively constant basal insulin coverage and reduces risk of hypoglycemia, especially nocturnal hypoglycemia, compared to NPH insulin 4, 5, 7, 8, 9

Monitoring Requirements

• Daily fasting blood glucose monitoring is essential during titration 2, 3
• Increase frequency of blood glucose monitoring during changes to insulin regimen 1
• Assess adequacy of insulin dose at every clinical visit 2, 3
• Reassess and modify therapy every 3-6 months once stable 2

Common Pitfalls to Avoid

• Delaying insulin therapy in patients not achieving glycemic goals 3
• Continuing to escalate basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia leads to overbasalization, suboptimal control, and increased hypoglycemia risk 2, 3
• Not adjusting doses based on self-monitoring of blood glucose 3
• Failing to continue metformin when adding or intensifying insulin therapy (unless contraindicated) 2, 3
• Not recognizing that insulin requirements change with weight changes, illness, or changes in physical activity 3
• Mixing or diluting insulin glargine with other insulins or solutions 1, 2