What is the recommended initial insulin regimen for a patient starting insulin therapy?

Starting Insulin Therapy

For patients with type 2 diabetes starting insulin therapy, initiate basal insulin at 10 units per day or 0.1-0.2 units/kg/day (whichever is lower for safety), administered once daily at the same time each day, preferably in conjunction with metformin. 1, 2

Initial Regimen Selection

Basal insulin alone is the most convenient and recommended initial insulin regimen for most patients with type 2 diabetes requiring insulin therapy. 3, 1, 2 This approach is simpler than complex multi-injection regimens and allows for gradual intensification if needed.

Preferred Basal Insulin Options

Long-acting insulin analogs are preferred over NPH insulin:

• Insulin glargine (U-100) 1, 4
• Insulin detemir 1
• Insulin degludec 1

These long-acting analogs reduce the risk of symptomatic and nocturnal hypoglycemia compared with NPH insulin, though the advantage is modest. 3

Starting Dose Calculation

Choose the lower of these two options to minimize hypoglycemia risk:

• Fixed dose: 10 units once daily 1, 2, 4
• Weight-based dose: 0.1-0.2 units/kg/day 3, 1, 2

For a 70 kg patient, this translates to 7-14 units per day using the weight-based approach, but starting at 10 units is safer and simpler. 2

Special Populations Requiring Lower Starting Doses

• Elderly patients: Start at 0.1 units/kg/day (lower end of range) 2
• Patients with renal insufficiency: Start at 0.1 units/kg/day 2
• Patients at high risk for hypoglycemia: Use conservative dosing 2

Administration Guidelines

• Administer subcutaneously once daily at the same time every day 4
• Timing can be any time of day, but consistency is critical 4
• Rotate injection sites within the same region (abdomen, thigh, or deltoid) to reduce lipodystrophy risk 4
• Never administer intravenously or via insulin pump 4
• Do not mix or dilute with other insulins 4

Dose Titration Strategy

Equip patients with a self-titration algorithm based on fasting blood glucose monitoring—this approach improves glycemic control. 3, 1, 2

Evidence-Based Titration Protocol

• Increase dose by 2 units every 3 days until fasting glucose reaches target (typically 80-130 mg/dL) without hypoglycemia 2
• If hypoglycemia occurs without clear cause, reduce dose by 10-20% 2
• Titration should occur over days to weeks as needed 3, 5

The goal is to achieve target fasting glucose levels, not just to reach a predetermined insulin dose. 2 Many patients require timely dose adjustments, and delays in titration lead to prolonged hyperglycemia.

Concomitant Medication Management

Continue These Medications

• Metformin: Always continue when initiating basal insulin 1
• SGLT2 inhibitors: May continue to improve glucose control and reduce total insulin dose 1
• Thiazolidinediones: May continue for similar benefits 1

Discontinue These Medications

• Sulfonylureas: Discontinue to reduce hypoglycemia risk 1
• DPP-4 inhibitors: Discontinue when using insulin regimens beyond basal-only 1
• GLP-1 receptor agonists: Discontinue when using complex insulin regimens (though may continue with basal-only) 1

When to Consider More Complex Regimens

If basal insulin has been titrated to achieve acceptable fasting glucose but HbA1c remains above target, consider adding:

1. GLP-1 receptor agonist (preferred option for many patients) 1, 2
2. Mealtime rapid-acting insulin starting with the largest meal 1, 2
   • Starting dose: 4 units, 0.1 units/kg, or 10% of basal dose 1
   • When adding prandial insulin, reduce basal dose by 4 units or 10% 2

Monitoring Requirements

• Increase frequency of blood glucose monitoring when initiating or changing insulin regimens 3, 4
• Self-monitor fasting blood glucose to guide titration 1, 2
• Evaluate adequacy of basal insulin dose at each visit 2
• Monitor for signs of over-basalization: elevated glucose differential between bedtime and morning, hypoglycemia, or high glucose variability 2

Critical Patient Education Components

Comprehensive education is critically important for any patient using insulin and must include: 3, 5

• Self-monitoring of blood glucose technique and interpretation 3, 5
• Recognition, prevention, and treatment of hypoglycemia 3, 5
• Dietary considerations and meal timing 3, 5
• The progressive nature of type 2 diabetes and why insulin is necessary 1, 5
• Self-titration algorithm for dose adjustments 1, 2

Common Pitfalls to Avoid

• Never delay insulin initiation in patients not achieving glycemic goals with other treatments 1, 2
• Never use insulin as a threat or describe it as personal failure or punishment 3, 1, 5
• Avoid over-basalization by pushing basal insulin doses too high when postprandial glucose is the real problem 5, 2
• Never use sliding scale insulin alone as the primary regimen, especially in type 1 diabetes 2
• Do not neglect hypoglycemia education—this is a critical safety issue 3, 5

Special Circumstances for Initial Regimen

Consider starting with basal insulin PLUS mealtime insulin (rather than basal alone) when: 1

• HbA1c ≥10-12% with symptomatic or catabolic features (weight loss, polyuria, polydipsia) 1
• Blood glucose levels ≥300-350 mg/dL 1
• Severe hyperglycemia with symptoms 1

In these situations, the patient requires more aggressive initial therapy to rapidly restore metabolic control.