What are the guidelines for writing an insulin prescription with special instructions?

How to Write an Insulin Prescription with Special Instructions

Start with 10 units of basal insulin (e.g., insulin glargine) subcutaneously once daily at the same time each day, or use 0.1-0.2 units/kg/day for insulin-naive patients with type 2 diabetes, and include explicit titration instructions directly on the prescription. 1, 2

Essential Prescription Components

Basic Prescription Elements

• Specify the exact insulin type and concentration: Write "insulin glargine 100 units/mL" (never just "insulin") to prevent dangerous medication errors between insulin products 2
• State the route clearly: "Subcutaneous injection into abdominal area, thigh, or deltoid" 2
• Timing instruction: "Once daily at the same time every day" (patient chooses the time, but must be consistent) 2
• Starting dose: "10 units subcutaneously once daily" OR "0.1-0.2 units/kg/day" for most insulin-naive type 2 diabetes patients 1, 3

Critical Special Instructions to Include

Titration Algorithm (choose one evidence-based approach):

• Standard approach: "Increase dose by 2 units every 3 days until fasting blood glucose reaches 80-130 mg/dL" 1, 3
• Alternative for faster titration: "Increase dose by 2-4 units once or twice weekly until fasting glucose target reached" 1, 3
• Specific glucose-based titration: If fasting glucose ≥180 mg/dL, increase by 4 units every 3 days; if 140-179 mg/dL, increase by 2 units every 3 days 3

Hypoglycemia Management Instructions:

• "If blood glucose <80 mg/dL or hypoglycemia symptoms occur, determine the cause and reduce dose by 10-20%" 1
• "Prescribe glucagon for emergent hypoglycemia" 1

Site Rotation Requirement:

• "Rotate injection sites within the same anatomical region to reduce risk of lipodystrophy and localized cutaneous amyloidosis" 2

Mixing Prohibition:

• "Do NOT dilute or mix with any other insulin or solution" 2
• This is particularly critical for insulin glargine due to its low pH 1, 3

Monitoring Requirements to Document

• Self-monitoring frequency: "Check fasting blood glucose daily during titration phase" 3
• Target fasting glucose: Specify individualized target, typically 80-130 mg/dL 1, 3
• Follow-up schedule: "Reassess every 3-6 months once stable" 1

Dose Adjustments for Special Populations

Renal Impairment:

• "Lower insulin doses required with decreased eGFR; titrate per clinical response" 1
• Start conservatively at the lower end of dosing range 1

Severe Hyperglycemia (A1C ≥9%, glucose ≥300 mg/dL):

• Consider higher starting doses of 0.3-0.4 units/kg/day 3
• May require immediate basal-bolus regimen rather than basal-only 1, 3

Hospitalized Patients:

• For insulin-naive or low-dose patients: 0.3-0.5 units/kg total daily dose, with half as basal 3
• For patients on high-dose home insulin (≥0.6 units/kg/day): reduce total daily dose by 20% to prevent hypoglycemia 3
• High-risk patients (elderly >65 years, renal failure, poor oral intake): use lower doses of 0.1-0.25 units/kg/day 3

Storage and Handling Instructions

• "Store unopened vials refrigerated at 36-46°F (2-8°C)" 4
• "Insulin in use may be kept at room temperature" 1
• "Avoid extreme temperatures (<36°F or >86°F) and excess agitation" 1, 4
• "Inspect vial before each use for clumping, frosting, precipitation, or changes in clarity—insulin glargine should appear clear" 1, 4

Critical Pitfalls to Avoid

Overbasalization Warning:

• When basal insulin dose approaches 0.5-1.0 units/kg/day without achieving A1C goal despite controlled fasting glucose, add prandial insulin rather than continuing to escalate basal insulin 1, 3
• Clinical signals of overbasalization include: basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability 3

Device-Specific Instructions:

• For SoloStar prefilled pens: "Never share pen between patients, even if needle is changed" 2
• "Refer to device-specific instructions for insulins compatible with different delivery systems" 1

Continuation of Foundation Therapy:

• Document: "Continue metformin unless contraindicated" 3
• Metformin should be maintained when adding or intensifying insulin therapy 3

When to Advance Beyond Basal Insulin

Add prandial insulin when:

• After 3-6 months of basal insulin optimization, fasting glucose reaches target but A1C remains above goal 3
• Basal insulin dose exceeds 0.5 units/kg/day and glucose remains elevated 3
• Start with 4 units of rapid-acting insulin before the largest meal OR 10% of current basal dose 1, 3