How do I titrate prandial insulin for a patient with hyperglycemia?

How to Titrate Prandial Insulin

Start prandial insulin with 4 units of rapid-acting insulin before the largest meal (or 10% of your basal insulin dose), then increase by 1-2 units every 3 days based on 2-hour postprandial glucose readings until postprandial glucose is <180 mg/dL. 1

When to Initiate Prandial Insulin

Add prandial insulin when any of these conditions are met:

• Basal insulin has been optimized (fasting glucose 80-130 mg/dL) but A1C remains above target after 3-6 months 1
• Basal insulin dose exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day without achieving glycemic targets 1
• Evidence of overbasalization is present: bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia episodes, or high glucose variability 1
• Significant postprandial hyperglycemia persists (>180 mg/dL at 2 hours post-meal) 1

Starting Dose Calculation

Choose one of these evidence-based approaches:

• 4 units of rapid-acting insulin before the largest meal 1
• 10% of current basal insulin dose (e.g., if on 40 units basal insulin, start with 4 units prandial) 1

Start with a single daily prandial dose before the meal causing the greatest postprandial glucose excursion 1, 2

Titration Algorithm

Increase prandial insulin by 1-2 units (or 10-15%) every 3 days based on 2-hour postprandial glucose readings 1

Specific Adjustment Rules:

• If 2-hour postprandial glucose consistently >180 mg/dL: Increase that meal's prandial dose by 1-2 units 1
• If hypoglycemia occurs without clear cause: Reduce the corresponding dose by 10-20% immediately 1
• Target postprandial glucose: <180 mg/dL at 2 hours post-meal 1

Advancing to Multiple Daily Prandial Doses

Add prandial insulin to additional meals sequentially if postprandial glucose remains >180 mg/dL at those times 1, 2

The progression typically follows:

1. Single prandial dose at largest meal 1
2. Second prandial dose at the meal with next highest postprandial excursion 2
3. Third prandial dose to complete basal-bolus regimen if needed 1

Each new prandial dose starts at 4 units and is titrated independently based on postprandial glucose after that specific meal 1

Monitoring Requirements

• Check 2-hour postprandial glucose after each meal where prandial insulin is given to guide dose adjustments 1
• Check pre-meal glucose to calculate correction doses if using insulin-to-carbohydrate ratios 1
• Reassess every 3 days during active titration 1
• Reassess every 3-6 months once stable to evaluate overall glycemic control 1

Timing of Administration

Administer rapid-acting insulin analogs 0-15 minutes before meals for optimal postprandial glucose control 1, 3

Never give rapid-acting insulin at bedtime as this significantly increases nocturnal hypoglycemia risk 1

Critical Thresholds and Warnings

When Basal Insulin is Too High:

Stop escalating basal insulin when it exceeds 0.5 units/kg/day—at this point, adding or intensifying prandial insulin is more appropriate than continuing to increase basal insulin 1

Signs of Overbasalization Requiring Prandial Addition:

• Basal insulin dose >0.5 units/kg/day 1
• Bedtime-to-morning glucose differential ≥50 mg/dL 1
• Hypoglycemia episodes 1
• High glucose variability throughout the day 1

Alternative to Prandial Insulin

Consider adding a GLP-1 receptor agonist (if not already on one) before advancing to prandial insulin to address postprandial hyperglycemia while minimizing hypoglycemia and weight gain risks 1

GLP-1 RA combined with basal insulin provides potent glucose-lowering with less weight gain and hypoglycemia than intensified insulin regimens 1

Common Pitfalls to Avoid

• 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 1
• Do not rely on correction (sliding scale) insulin alone—scheduled prandial insulin with correction doses as adjunct is superior 1
• Do not give rapid-acting insulin at bedtime to correct hyperglycemia—this causes nocturnal hypoglycemia 1
• Do not abruptly discontinue oral medications when starting prandial insulin—continue metformin unless contraindicated 3

Foundation Therapy Maintenance

Continue metformin at maximum tolerated dose (up to 2000-2550 mg daily) when adding or intensifying prandial insulin, as this combination provides superior glycemic control with reduced total insulin requirements and less weight gain 1