How can I switch from Humalog (insulin lispro) to NovoRapid (insulin aspart) using a unit‑for‑unit conversion and safely titrate the doses while monitoring blood glucose?

Switching from Humalog to NovoRapid: Unit-for-Unit Conversion

You can switch directly from Humalog (insulin lispro) to NovoRapid (insulin aspart) using a 1:1 unit-for-unit conversion without any dose adjustment, as both rapid-acting insulin analogs have nearly identical pharmacokinetic and pharmacodynamic profiles. 1, 2

Direct Conversion Protocol

• Use the exact same dose of NovoRapid that you were using with Humalog—no calculation or adjustment is needed 1, 2
• Both insulins have equivalent onset of action (0.25–0.5 hours), peak action (1–3 hours), and duration (3–5 hours) 1
• Direct comparison studies in type 1 diabetes patients confirm that insulin aspart and insulin lispro produce equivalent blood glucose excursions and maximum postprandial glucose levels 2

Administration Timing

• Inject NovoRapid 5–10 minutes before meals (compared to Humalog's 0–15 minutes before meals) 3
• Both insulins should be administered subcutaneously into the abdominal area, thigh, buttocks, or upper arm 3
• Rotate injection sites within the same region from one injection to the next to reduce risk of lipodystrophy and localized cutaneous amyloidosis 3

Monitoring During the Switch

• Check blood glucose before each meal and 2 hours postprandially for the first 3–7 days after switching to confirm equivalent glycemic control 4
• Target fasting/pre-meal glucose of 80–130 mg/dL and postprandial glucose <180 mg/dL 4
• If hypoglycemia occurs (glucose <70 mg/dL) without clear cause, reduce the dose by 10–20% immediately 4

Dose Titration After Switching

• Adjust each meal dose by 1–2 units (or 10–15%) every 3 days based on 2-hour postprandial glucose readings if targets are not met 4
• The titration protocol is identical for both insulins because their pharmacodynamic effects are equivalent 1, 2

Special Considerations for Insulin Pump Users

• NovoRapid can be used in continuous subcutaneous insulin infusion (CSII) pumps labeled for use with NovoLog 3
• Do not mix NovoRapid with other insulins or diluents in the pump 3
• Change the reservoir at least every 7 days and do not expose to temperatures >98.6°F (37°C) 3
• Some evidence suggests NovoRapid may provide slightly more stable postprandial glucose when used in CSII compared to Humalog, though both are highly effective 5

Common Pitfalls to Avoid

• Do not reduce or increase the dose when switching—the 1:1 conversion is supported by direct comparative trials showing pharmacodynamic equivalence 1, 2
• Do not administer at bedtime as a sole correction dose, as this markedly increases nocturnal hypoglycemia risk for both insulins 4
• Do not delay the switch due to concerns about different action profiles—clinical trials demonstrate no clinically meaningful differences in glucose control between the two analogs 2