Mixtard 15 Units Composition
15 units of Mixtard insulin contains approximately 10.5 units of NPH (intermediate-acting) insulin and 4.5 units of regular (short-acting) insulin, as Mixtard is a premixed 70/30 formulation (70% NPH and 30% regular insulin).
Understanding Mixtard Formulation
Mixtard is a premixed insulin product that combines both basal and prandial insulin components in a single injection 1. The standard formulation is:
- 70% NPH insulin (intermediate-acting, provides basal coverage)
- 30% Regular insulin (short-acting, provides prandial coverage)
Therefore, when administering 15 units of Mixtard:
- NPH component: 15 × 0.70 = 10.5 units
- Regular insulin component: 15 × 0.30 = 4.5 units
Clinical Characteristics of This Combination
NPH (Neutral Protamine Hagedorn) insulin in Mixtard provides intermediate-acting coverage with a peak action at 4-6 hours after administration 1. This component addresses basal insulin needs throughout the day 1.
Regular insulin provides prandial coverage and must be injected at least 30 minutes before meals for optimal effect 2. This short-acting component addresses postprandial glucose excursions.
Practical Mixing Considerations
The American Diabetes Association explicitly endorses mixing NPH with regular insulin as a legitimate treatment strategy 2. Key advantages include:
- Reduced injection burden - combining both insulins in one syringe reduces daily injections 2
- Cost-effectiveness - represents the least expensive insulin regimen available 2
- Maintained stability - NPH's protamine-based formulation maintains stability when mixed with regular insulin 2
Important caveat: NPH can be mixed with rapid-acting or short-acting insulins without significant blunting of onset, but insulin glargine cannot be mixed with other insulins due to its low pH diluent 3.
Dosing Context
When premixed insulin like Mixtard is used, typical dosing patterns include giving 2/3 of total daily dose before breakfast and 1/3 before dinner 2. This 15-unit dose would fit into such a regimen depending on the patient's total daily insulin requirements and meal timing 1.
The regimen requires relatively consistent mealtimes and carbohydrate intake, and carries specific hypoglycemia risks including greater risk of nocturnal hypoglycemia 2.