What is the initial insulin administration recommendation for patients requiring insulin therapy?

Initial Insulin Administration for Patients Requiring Insulin Therapy

Start with basal insulin at 10 units once daily or 0.1-0.2 units/kg/day, administered at the same time each day, in combination with metformin (unless contraindicated). 1, 2, 3

Starting Dose Selection

Standard Initiation for Type 2 Diabetes

• For insulin-naive patients with type 2 diabetes, initiate with 10 units once daily OR 0.1-0.2 units/kg/day of basal insulin (glargine, detemir, degludec, or NPH). 1, 2, 3
• For a 70 kg patient, this translates to 7-14 units per day based on the degree of hyperglycemia. 1
• Administer at the same time every day, regardless of which time is chosen. 2, 3

Severe Hyperglycemia Requires Higher Starting Doses

• When HbA1c ≥9%, blood glucose ≥300-350 mg/dL, or HbA1c 10-12% with symptomatic/catabolic features, consider starting with 0.3-0.4 units/kg/day or a basal-bolus regimen immediately. 2, 4
• This more aggressive approach achieves glycemic targets faster in patients with marked hyperglycemia. 4

Type 1 Diabetes Initiation

• For type 1 diabetes, start with approximately one-third of total daily insulin requirements as basal insulin, with the remainder as short-acting premeal insulin. 3
• 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. 1, 4
• Approximately 50% should be basal insulin and 50% as prandial insulin divided among meals. 1, 4

Preferred Basal Insulin Options

• Long-acting analogs (glargine, detemir, or degludec) are preferred over NPH insulin. 2
• These provide more consistent basal coverage with lower risk of nocturnal hypoglycemia compared to NPH. 5, 6

Concomitant Medications

• Continue metformin when initiating insulin therapy unless contraindicated. 1, 2
• Consider continuing one additional non-insulin agent (SGLT2 inhibitor or thiazolidinedione may reduce total insulin requirements). 2
• Discontinue sulfonylureas when starting insulin to reduce hypoglycemia risk. 2

Dose Titration Protocol

Standard Titration Algorithm

• Increase basal insulin by 2 units every 3 days if fasting glucose is 140-179 mg/dL. 1, 4
• Increase by 4 units every 3 days if fasting glucose is ≥180 mg/dL. 1, 4
• Target fasting glucose of 80-130 mg/dL (4.4-7.2 mmol/L). 1, 4

Patient Self-Titration

• Equipping patients with self-titration algorithms improves glycemic control more effectively than clinic-managed titration alone. 1, 2
• Patient-managed approach: increase by 2 units every 3 days in the absence of hypoglycemia (glucose <72 mg/dL). 7
• This approach achieved greater HbA1c reductions (-1.22% vs -1.08%) compared to clinic-only management. 7

Hypoglycemia Management

• If hypoglycemia occurs without clear cause, reduce the dose by 10-20% immediately. 1, 4
• If more than 2 fasting glucose values per week are <80 mg/dL, decrease basal insulin by 2 units. 4

Special Populations

Elderly or Renal Insufficiency

• Start with the lower end of the dosing range (0.1 units/kg/day) to minimize hypoglycemia risk. 1
• For hospitalized high-risk patients (elderly >65 years, renal failure, poor oral intake), consider 0.1-0.25 units/kg/day. 4

Patients on Corticosteroids

• Consider NPH insulin in the morning to counteract steroid-induced daytime hyperglycemia. 1
• For patients with diabetes on steroids, add 0.1-0.3 units/kg/day glargine to usual regimen. 4

Critical Threshold: When to Add Prandial Insulin

Recognizing Overbasalization

• 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, 4
• Clinical signals of overbasalization include:
  • Bedtime-to-morning glucose differential ≥50 mg/dL 4
  • Hypoglycemia episodes 4
  • High glucose variability 4
  • Fasting glucose at target but HbA1c remains above goal after 3-6 months 1, 2

Adding Prandial Coverage

• Start with 4 units of rapid-acting insulin before the largest meal OR 10% of the basal dose. 1, 2
• Reduce basal insulin by 4 units or 10% when adding prandial insulin. 1
• Alternatively, consider adding a GLP-1 receptor agonist to address postprandial hyperglycemia while minimizing hypoglycemia and weight gain. 2, 4

Administration Technique

Injection Guidelines

• Administer subcutaneously into the abdominal area, thigh, or deltoid. 3
• Rotate injection 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

Critical Warnings

• Never administer intravenously or via an insulin pump. 3
• Do not dilute or mix insulin glargine with any other insulin or solution. 3
• Insulin glargine's low pH makes mixing incompatible with other insulins. 4

Monitoring Requirements

• Increase frequency of blood glucose monitoring when initiating or changing insulin regimens. 1, 3
• Daily fasting blood glucose monitoring is essential during titration. 1, 4
• Evaluate adequacy of basal insulin dose at each visit, looking for signs of overbasalization. 1, 4

Common Pitfalls to Avoid

• Do not delay insulin initiation in patients not achieving glycemic goals with oral medications. 1, 2
• Do not use insulin as a threat or describe it as a sign of personal failure. 2
• Avoid using only sliding scale insulin, especially in type 1 diabetes. 1
• 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 and suboptimal control. 2, 4

Patient Education Essentials

• Provide comprehensive education on self-monitoring of blood glucose, diet, exercise, and recognition/prevention/treatment of hypoglycemia. 2
• Educate patients on the progressive nature of type 2 diabetes and the role of insulin therapy. 2
• Teach proper insulin injection technique and site rotation. 2
• Provide "sick day" management rules and insulin storage/handling instructions. 2