What is the recommended initial dose and management strategy for starting Mixtard (insulin) in a patient with steroid-induced hyperglycemia and a premeal blood glucose level of hyperglycemia at night?

Starting Mixtard for Steroid-Induced Hyperglycemia with Premeal Glucose 400 mg/dL at Night

For a patient with steroid-induced hyperglycemia and premeal glucose of 400 mg/dL at night, this represents severe hyperglycemia requiring hospital admission for continuous intravenous insulin infusion rather than starting Mixtard as an outpatient. 1

Immediate Management Priority

• Admit to hospital immediately - glucose >400 mg/dL (>22 mmol/L) represents Grade 4 toxicity requiring inpatient management with IV insulin therapy, volume resuscitation, and evaluation for hyperosmolar hyperglycemic state 1
• Continuous insulin infusion is the preferred regimen for severe steroid-induced hyperglycemia, particularly when glucose exceeds 400 mg/dL 2, 1
• Target glucose 140-180 mg/dL (7.8-10.0 mmol/L) during IV insulin therapy 1
• Monitor glucose every 1-2 hours initially, then every 2-4 hours once stable 1

Why Mixtard is NOT the Right Choice Here

• Mixtard (premixed insulin) is only appropriate for moderate steroid-induced hyperglycemia, not severe cases with glucose >400 mg/dL 2
• The patient requires immediate intensive insulin therapy that can be rapidly titrated, which subcutaneous premixed insulin cannot provide 2, 1
• Starting with subcutaneous insulin at this glucose level delays appropriate treatment and increases risk of hyperosmolar hyperglycemic state 2, 1

Critical Assessment Points

• Evaluate for hyperosmolar hyperglycemic state: check serum osmolality, electrolytes (particularly potassium - hypokalaemia occurs in ~50% of cases), renal function, and mental status 1
• Determine steroid type, dose, and timing - this glucose level suggests either very high-dose steroids or multiple daily dosing 2, 3
• Assess for symptoms of severe hyperglycemia: polyuria, polydipsia, altered mental status, profound dehydration 2

Transition to Subcutaneous Insulin (Once Stabilized)

After glucose is controlled with IV insulin and the patient is stable, transition to subcutaneous insulin based on steroid timing:

If Steroids Given in Morning (Most Common)

• Use NPH insulin 0.3-0.5 units/kg/day given in the morning to match the afternoon/evening peak hyperglycemic effect 3, 4
• For this patient with severe hyperglycemia, start at the higher end (0.5 units/kg/day) or even higher (40-60% increase) given the glucose level of 400 mg/dL 4, 5
• NPH peaks 4-6 hours after administration, aligning with the 6-9 hour peak hyperglycemic effect of morning glucocorticoids 3, 4
• Add rapid-acting insulin (aspart or lispro) before meals at 1 unit per 10-15 grams of carbohydrate, with correction doses for hyperglycemia 3, 5

If Steroids Given at Night

• Switch to long-acting basal insulin (glargine or detemir) given at bedtime at 0.3-0.5 units/kg/day, as NPH will not adequately cover the overnight and next-day hyperglycemia pattern 3
• Add rapid-acting insulin before breakfast and lunch, as the hyperglycemic peak will occur overnight and into the following day 3

Why NOT Mixtard Specifically

• Mixtard (30/70 mix) lacks the flexibility needed for severe steroid-induced hyperglycemia - you cannot independently adjust the basal and prandial components 2
• Patients achieving normoglycemia require 58.1% of total daily dose as nutritional (prandial) insulin, not the fixed 30% in Mixtard 5
• The 70% NPH component in Mixtard may cause nocturnal hypoglycemia since steroid-induced hyperglycemia often normalizes overnight 2, 3

Monitoring Protocol

• Four-times-daily glucose monitoring (fasting and 2 hours after each meal) - do NOT rely on fasting glucose alone as this misses the peak hyperglycemic effect 3, 4, 1
• Focus on afternoon/evening readings (2-3 PM and 6-8 PM) as these capture the peak steroid effect 3, 4
• Target range: 5-10 mmol/L (90-180 mg/dL) once transitioned to subcutaneous insulin 3, 4

Dose Adjustment Strategy

• As steroids are tapered, reduce insulin doses proportionally - this is a critical pitfall to avoid 3, 4, 1
• Insulin requirements can decline rapidly after steroid discontinuation, leading to hypoglycemia if not adjusted 2, 3
• Reduce insulin by the same percentage as steroid dose reduction 1
• Increase insulin by 2 units every 3 days if target not achieved 3

Common Pitfalls to Avoid

• Using only sliding-scale correction insulin without scheduled basal/prandial insulin - this leads to poor glycemic control and is strongly discouraged 1, 5
• Relying on fasting glucose alone - this misses the peak hyperglycemic effect occurring 6-9 hours after morning steroid administration 3, 4, 1
• Starting subcutaneous insulin for glucose >400 mg/dL - this delays appropriate IV insulin therapy 1
• Failing to reduce insulin when steroids are tapered - this causes severe hypoglycemia 3, 4, 1
• Using oral antidiabetic agents alone for high-dose steroid therapy - these are insufficient 4, 1

Patient Education Requirements

• Warn about hyperosmolar hyperglycemic state: if glucose meter reads "HI" or persistently >20 mmol/L (>360 mg/dL), seek immediate medical attention 4
• Teach glucose monitoring technique and frequency (four times daily) 4
• Educate on symptoms of severe hyperglycemia and hypoglycemia 2, 4
• Emphasize that insulin doses must be adjusted as steroids are tapered 2, 3

When to Involve Endocrinology

• All patients with glucose >400 mg/dL should have endocrinology consultation 1
• Early consultation is particularly important for patients requiring extraordinarily high insulin doses or developing complications 1