What is the appropriate initial insulin dosage for a 35-year-old male with hyperglycemia (Fasting Blood Sugar (FBS) of 398 and Postprandial Blood Sugar (PPBS) of 540)?

Initial Insulin Dosing for Severe Hyperglycemia

For a 35-year-old male with FBS 398 mg/dL and PPBS 540 mg/dL, start basal-bolus insulin therapy immediately with a total daily dose of 0.3-0.5 units/kg/day, divided as 50% basal insulin (insulin glargine) once daily and 50% as prandial insulin (rapid-acting insulin) split among three meals. 1, 2

Rationale for Immediate Basal-Bolus Therapy

This patient's severe hyperglycemia (FBS 398 mg/dL, PPBS 540 mg/dL) warrants aggressive insulin therapy from the outset rather than starting with basal insulin alone. 1, 2

• Blood glucose ≥300-350 mg/dL with symptomatic hyperglycemia requires immediate basal-bolus insulin rather than basal-only therapy. 1, 2
• Insulin is the most effective glucose-lowering agent when blood glucose levels are this severely elevated. 1, 3
• Starting with basal insulin alone would be insufficient to control both fasting and postprandial hyperglycemia at these levels. 1, 2

Specific Dosing Algorithm

Step 1: Calculate Total Daily Dose (TDD)

Assuming the patient weighs 70 kg (adjust based on actual weight):

• Start with 0.3-0.5 units/kg/day as TDD for severe hyperglycemia. 1, 2
• For a 70 kg patient: 21-35 units/day total (use 0.4 units/kg = 28 units/day as middle estimate). 1, 2

Step 2: Divide Into Basal and Prandial Components

• Give 50% as basal insulin glargine (Lantus) once daily: 14 units at bedtime. 1, 2
• Give 50% as prandial rapid-acting insulin divided among three meals: approximately 4-5 units before each meal. 1, 2

Step 3: Titration Schedule

Basal Insulin Titration: 1, 2

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

Prandial Insulin Titration: 1, 2

• Increase each meal dose by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings. 1, 2
• Target postprandial glucose: <180 mg/dL. 1

Foundation Therapy

• Start or continue metformin 1000 mg twice daily (2000 mg/day total) unless contraindicated. 1, 3
• Metformin reduces total insulin requirements and provides complementary glucose-lowering effects. 1, 3
• Maximum effective metformin dose is up to 2500 mg/day. 3

Administration Guidelines

Basal Insulin (Glargine): 4

• Administer subcutaneously once daily at the same time each day (typically bedtime). 4
• Rotate injection sites within the same region (abdomen, thigh, or deltoid). 4
• Do not dilute or mix with any other insulin. 4

Prandial Insulin (Rapid-Acting): 1, 5

• Administer 0-15 minutes before each meal. 2
• Use insulin lispro, aspart, or glulisine. 1, 5

Monitoring Requirements

• Daily fasting blood glucose monitoring is essential during titration. 1, 2
• Monitor 2-hour postprandial glucose after each meal initially. 1, 2
• Check HbA1c every 3 months during intensive titration. 2
• Assess adequacy of insulin doses at every clinical visit. 1, 2

Critical Thresholds and Warning Signs

• When basal insulin exceeds 0.5 units/kg/day without achieving targets, intensify prandial insulin rather than continuing to escalate basal insulin alone. 1, 2
• Watch for signs of overbasalization: bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, high glucose variability. 1, 2
• If correction doses are needed daily, the underlying insulin regimen requires adjustment. 6

Patient Education Essentials

Hypoglycemia Recognition and Treatment: 1, 2

• Treat blood glucose ≤70 mg/dL with 15 grams of fast-acting carbohydrate. 2
• Recheck glucose in 15 minutes and repeat treatment if still <70 mg/dL. 2
• Prescribe glucagon for emergent hypoglycemia. 1

Injection Technique: 1, 2

• Teach proper insulin injection technique and site rotation. 2
• Avoid injecting into areas of lipodystrophy. 4

Self-Monitoring: 1, 2

• Instruct on self-monitoring of blood glucose and self-titration algorithms. 1, 2
• Provide written instructions for insulin dose adjustments based on glucose patterns. 3

Common Pitfalls to Avoid

• Do not delay basal-bolus therapy by starting with basal insulin alone at these glucose levels—this prolongs severe hyperglycemia and increases complication risk. 1, 3
• Do not rely solely on sliding scale (correction) insulin without scheduled basal-bolus therapy—this approach is strongly discouraged and ineffective. 1, 6, 3
• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia with prandial insulin. 1, 2
• Do not discontinue metformin when starting insulin—continue unless contraindicated. 1, 3
• Do not wait weeks between dose adjustments—titrate aggressively every 3 days to achieve targets rapidly. 1, 2

Alternative Consideration

• If cost or adherence is a major concern, consider twice-daily premixed insulin (70/30 or 75/25) as a simpler alternative, though it offers less flexibility than basal-bolus therapy. 3
• Once glycemic control improves, consider adding a GLP-1 receptor agonist to reduce insulin requirements and provide cardiovascular benefits. 1, 3