What are the starting doses for basal (long-acting) insulin, such as glargine (insulin glargine) or detemir (insulin detemir), and premix (mixed) insulin?

Starting Doses for Basal and Premix Insulin

For basal insulin in type 2 diabetes, start with 10 units once daily or 0.1-0.2 units/kg/day; for premix insulin, initiate with twice-daily dosing at 4 units per injection or 0.1-0.2 units/kg/day divided between two doses. 1, 2, 3

Basal Insulin Starting Doses

Type 2 Diabetes (Insulin-Naive Patients)

• Standard initiation: 10 units once daily administered at the same time each day, regardless of meal timing 1, 2, 3
• Weight-based alternative: 0.1-0.2 units/kg/day once daily for patients requiring more individualized dosing 1, 2, 3
• Severe hyperglycemia (A1C ≥9% or glucose ≥300-350 mg/dL): 0.3-0.4 units/kg/day to achieve targets faster 1, 2
• Continue metformin unless contraindicated when initiating basal insulin 4, 2

Type 1 Diabetes

• Starting dose: approximately one-third of total daily insulin requirements as basal insulin 3
• Total daily insulin typically ranges from 0.4-1.0 units/kg/day, with 0.5 units/kg/day being standard for metabolically stable patients 1, 2
• The remaining two-thirds should be provided as short-acting, premeal insulin 3

Dose Titration Protocol

• Increase by 2 units every 3 days if fasting glucose is 140-179 mg/dL 1, 2
• Increase by 4 units every 3 days if fasting glucose is ≥180 mg/dL 1, 2
• Target fasting plasma glucose: 80-130 mg/dL 1, 2
• If hypoglycemia occurs, reduce dose by 10-20% immediately 1, 2

Premix Insulin Starting Doses

Initial Dosing Strategy

• Administer twice daily (before breakfast and before dinner) 5
• Starting dose: 4 units per injection or 0.1-0.2 units/kg/day divided between the two doses 5
• Available formulations include 70/30 NPH/regular, 70/30 aspart mix, 75/25 lispro mix, or 50/50 lispro mix 5

When to Consider Premix Insulin

• Premix insulin is appropriate when basal insulin has been titrated to acceptable fasting glucose but A1C remains above target 4, 5
• Consider converting from basal insulin to twice-daily premix when additional prandial coverage is needed but multiple daily injections are not feasible 4
• Premix provides a simple, convenient means of spreading insulin across the day compared to basal-bolus regimens 4

Medication Management with Premix

• Continue metformin when initiating premix insulin 5
• Discontinue sulfonylureas, DPP-4 inhibitors, and GLP-1 receptor agonists when starting multiple-dose premixed insulin 5

Critical Thresholds and Warning Signs

Recognizing Overbasalization

• When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add prandial insulin or switch to premix rather than continuing to escalate basal insulin alone 1, 2
• Clinical signals of overbasalization include: bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability 1

Severe Hyperglycemia Requiring Immediate Basal-Bolus

• For patients with A1C 10-12% with symptomatic or catabolic features, or blood glucose ≥300-350 mg/dL, start basal-bolus insulin immediately rather than basal insulin alone 1, 2

Common Pitfalls to Avoid

• Never 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 suboptimal control and increased hypoglycemia risk 1
• Avoid using premixed insulin in hospital settings due to unacceptably high rates of iatrogenic hypoglycemia 1
• Do not dilute or mix insulin glargine with any other insulin or solution due to its low pH 3
• Ensure patients understand that insulin is not a sign of personal failure but rather a necessary treatment for progressive disease 2

Special Populations

Hospitalized Patients

• For insulin-naive or low-dose patients: 0.3-0.5 units/kg/day total daily dose, with half as basal insulin 1
• For patients on high-dose home insulin (≥0.6 units/kg/day): reduce total daily dose by 20% upon hospitalization to prevent hypoglycemia 1
• Lower doses (0.1-0.25 units/kg/day) for high-risk patients: elderly (>65 years), renal failure, or poor oral intake 1