Insulin Premixed
Combination of intermediate and rapid-acting insulin providing both basal and prandial coverage in a single injection.
Chemical Identity
| Property | Value |
|---|---|
| Formulation | Fixed-ratio insulin combinations |
| Examples | 70/30 NPH/Regular, 75/25 Lispro Mix |
| Peptide Class | Insulin Combination |
| Route | SC injection |
Structure
Premixed insulins contain a fixed ratio of intermediate-acting (NPH or protamine-bound analog) and rapid/short-acting insulin. Common formulations include 70/30 (70% NPH, 30% regular), 75/25 (75% protamine lispro, 25% lispro), and 70/30 (70% protamine aspart, 30% aspart).
Mechanism of Action
The rapid/short-acting component provides prandial coverage for the upcoming meal, while the intermediate component provides basal coverage until the next injection. This mimics physiological insulin secretion with the convenience of fewer injections.
Clinical Applications
- Type 2 diabetes: Simplified insulin regimen for patients struggling with basal-bolus
- Twice-daily dosing: Before breakfast and dinner
- Patients with adherence concerns: Fewer injections than basal-bolus
- Transitional therapy: Moving from basal-only to basal-bolus
Pharmacokinetics
- Onset: 15-60 minutes (depending on rapid component)
- Peak: Dual peaks (rapid component 1-2 hours, intermediate 4-12 hours)
- Duration: 12-24 hours
- Dosing flexibility: Limited (fixed ratio)
- Route: SC injection
Safety and Side Effects
Hypoglycemia (timing-dependent on meals), weight gain, injection site reactions, and inflexibility in dosing. Cannot independently adjust basal and prandial components.
References
- Raskin, P., et al. (2005). Premixed insulin analogs. Diabetes Care, 28, 1684-1690.
- Garber, A.J., et al. (2006). Premixed insulin in type 2 diabetes. Endocrine Practice, 12, 11-20.
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