A patient on basal insulin glargine (Lantus) is to be started on rapid‑acting insulin aspart (Novorapid) before meals; how should the initial mealtime dose be started and what titration schedule should be provided for home use, with blood glucose targets expressed in mmol/L?

Starting NovoRapid (Insulin Aspart) in a Patient on Basal Insulin

Start NovoRapid at 4 units before the largest meal or the meal with the highest postprandial glucose excursion, and provide a titration schedule to increase by 1-2 units every 3 days targeting premeal glucose of 4.0-7.0 mmol/L. 1

Initial Dosing Strategy

When adding prandial insulin to established basal insulin therapy, the most recent ADA 2025 guidelines provide clear direction:

• Starting dose: 4 units OR 10% of your patient's current basal insulin dose (whichever is applicable) 1
• Administer before the largest meal or the meal causing the greatest postprandial glucose rise
• If the patient's A1C is <8% (<64 mmol/mol), consider reducing the Lantus dose by 4 units or 10% to minimize hypoglycemia risk 1

The AACE 2023 guidelines align with this approach, recommending either 5 units or 10% of basal dose as starting points 2. Since your patient is already on stable basal insulin, the conservative 4-unit start is appropriate.

Home Titration Instructions for the Patient

Provide this structured titration schedule:

Dose Adjustment Algorithm

Increase NovoRapid by 1-2 units every 3 days based on the next meal's premeal glucose (the glucose reading before the subsequent meal) 1:

• If premeal glucose >7.8 mmol/L: increase by 2 units
• If premeal glucose 6.1-7.8 mmol/L: increase by 1 unit
• If premeal glucose 4.0-6.0 mmol/L: maintain current dose
• If premeal glucose <4.0 mmol/L: decrease by 10-20% (1-2 units) 1

Target Glucose Ranges

• Premeal glucose target: 4.0-6.1 mmol/L (more lenient: 6.1-7.2 mmol/L depending on hypoglycemia risk)
• 2-hour postprandial target: <10.0 mmol/L 2

Timing of Administration

Administer NovoRapid 0-15 minutes before the meal 1. Research demonstrates that giving rapid-acting insulin 15 minutes before meals produces superior postprandial control compared to at-meal or 30-minutes-before timing, without increasing hypoglycemia 3. However, for practical adherence, 0-15 minutes premeal is acceptable.

Progression to Multiple Daily Injections

If A1C remains above goal after optimizing the single mealtime dose:

1. Add a second injection before the next largest meal (start at 4 units, titrate similarly)
2. Add a third injection if needed to achieve full basal-bolus coverage 1

The AACE guidelines suggest progressing when premeal glucose remains >6.1-7.8 mmol/L despite adequate titration of the first dose 2.

Critical Safety Considerations

Hypoglycemia Management

• If glucose <3.9 mmol/L: reduce the corresponding NovoRapid dose by 10-20% 1
• If glucose <2.2 mmol/L: reduce by 20-40% 2
• Ensure the patient has fast-acting carbohydrates (15g glucose tablets or juice) available

Common Pitfalls to Avoid

1. Therapeutic inertia: Don't wait months to titrate—adjust every 3 days as planned 1
2. Over-basalization: If Lantus dose is very high (>0.5 units/kg/day) with poor A1C but good fasting glucose, this signals need for prandial insulin rather than more basal 1, 2
3. Meal consistency: Emphasize that NovoRapid dose should match carbohydrate intake; larger meals may eventually require proportionally higher doses
4. Injection site rotation: Rotate within the same region (abdomen preferred for fastest absorption) to prevent lipohypertrophy 4

Monitoring Requirements

• Daily: Premeal glucose before the meal where NovoRapid is given, plus the next meal's premeal reading
• Weekly: Review glucose log and adjust dose
• 3 months: Check A1C to assess overall control 1

This stepwise approach balances efficacy with safety, allowing gradual intensification while minimizing hypoglycemia risk. The evidence strongly supports starting conservatively with a single injection and building up based on individualized glucose patterns rather than immediately implementing a full basal-bolus regimen.