What dose of human mixtard 30/70 (insulin) would be suitable for a 70kg patient during discharge, given their current regimen of injection glargine (insulin glargine) at 8 units and total regular insulin (short-acting insulin) at 26 units per day?

Converting from Basal-Bolus to Mixtard 30/70 at Discharge

For a patient on 8 units of glargine and 26 units total regular insulin daily, start Mixtard 30/70 at approximately 17 units twice daily (total 34 units/day), given before breakfast and dinner.

Calculation Rationale

Total Daily Dose Assessment

• The current regimen provides 34 units total daily insulin (8 units glargine + 26 units regular) 1
• When converting to premixed insulin, the American Diabetes Association recommends using approximately 80% of the hospital basal dose as a starting point for discharge planning 1
• For Mixtard 30/70 (70% NPH/30% regular), the total daily dose should be divided into two injections, typically with 2/3 given before breakfast and 1/3 before dinner 1

Mixtard 30/70 Dosing Strategy

• Initial total daily dose: Start with 34 units/day (matching current total) 1
• Distribution: Give approximately 22 units before breakfast (65%) and 12 units before dinner (35%) 1
• Alternative conservative approach: Use 17 units twice daily (total 34 units), which provides a more balanced split and may be safer initially 1

Critical Considerations for Discharge

Patient Selection Appropriateness

• Premixed insulins like Mixtard 30/70 are appropriate for patients requiring both basal and prandial coverage who prefer fewer injections 1
• The American Diabetes Association notes that premixed insulin regimens are noninferior to basal-bolus therapy with similar hypoglycemia rates in type 2 diabetes 1
• However, randomized trials show premixed insulins have significantly increased hypoglycemia rates in hospitalized patients compared to basal-bolus regimens 2

Titration Instructions

• Increase the morning dose by 2 units every 3 days if pre-dinner glucose is >180 mg/dL 1, 3
• Increase the evening dose by 2 units every 3 days if fasting glucose is >130 mg/dL 1, 3
• If hypoglycemia occurs, reduce the corresponding dose by 10-20% immediately 1

Administration Guidelines

Timing and Technique

• Administer Mixtard 30/70 immediately before breakfast and immediately before dinner (within 15 minutes of eating) 1
• The 30% regular insulin component requires meal consumption within 30 minutes of injection 4
• Do not mix Mixtard 30/70 with any other insulin in the same syringe 1

Monitoring Requirements

• Check fasting blood glucose and pre-dinner glucose daily during initial titration 1, 3
• Target fasting glucose: 80-130 mg/dL 1
• Target pre-meal glucose: 90-150 mg/dL 2

Common Pitfalls to Avoid

Dosing Errors

• Never continue basal-bolus regimen alongside Mixtard 30/70—this causes dangerous insulin stacking 1, 2
• Avoid giving Mixtard 30/70 at bedtime instead of dinner, as the regular insulin component increases nocturnal hypoglycemia risk 2
• Do not use correction doses of rapid-acting insulin at bedtime with this regimen 2

Meal Timing Issues

• Patients must eat regular meals at consistent times—Mixtard 30/70 is inappropriate for those with erratic eating patterns 1
• Missing meals after Mixtard 30/70 injection significantly increases hypoglycemia risk 1

Alternative Consideration

When Basal-Bolus May Be Preferred

• If the patient's admission HbA1c was >9%, consider continuing separate basal and prandial insulins rather than switching to premixed 1
• Patients requiring >0.5 units/kg/day total insulin may achieve better control with continued basal-bolus therapy 1
• For a 70kg patient, 34 units/day represents 0.49 units/kg/day—near the threshold where basal-bolus offers advantages 1, 2

Foundation Therapy

• Continue metformin unless contraindicated, even when using Mixtard 30/70 1
• Discontinue sulfonylureas to prevent hypoglycemia when using premixed insulin 1