What is the equivalent dose of insulin glargine for a 60-year-old female diabetic patient taking 25 units of Treva (NPH insulin) daily?

Converting from Treva (NPH Insulin) to Insulin Glargine

For a 60-year-old female patient taking 25 units of Treva (NPH insulin) daily, start insulin glargine at 20 units once daily (80% of the NPH dose). 1

Conversion Dosing Algorithm

When switching from once-daily NPH insulin to once-daily insulin glargine, the FDA-approved starting dose is the same as the NPH dose being discontinued. 1 However, when switching from twice-daily NPH to once-daily insulin glargine, reduce the total NPH dose by 20% (use 80% of the total NPH dosage). 1

Determining the Conversion Dose

Since the question states "25 units per day" without specifying once or twice daily administration:

• If the patient takes NPH once daily (25 units): Start insulin glargine at 25 units once daily 1
• If the patient takes NPH twice daily (total 25 units): Start insulin glargine at 20 units once daily (80% of 25 units) 1

The most common clinical scenario is twice-daily NPH dosing, making 20 units the most likely appropriate starting dose. 1

Administration Instructions

• Administer insulin glargine subcutaneously once daily at the same time every day (can be given at any time, but consistency is critical) 1
• Rotate injection sites within the same region (abdomen, thigh, or deltoid) to reduce lipodystrophy risk 1
• Do not dilute or mix insulin glargine with any other insulin or solution 1
• Never administer intravenously or via insulin pump 1

Titration Protocol After Conversion

Increase the insulin glargine dose by 2-4 units every 3 days until fasting blood glucose reaches 80-130 mg/dL. 2

• If fasting glucose is 140-179 mg/dL: Increase by 2 units every 3 days 2
• If fasting glucose ≥180 mg/dL: Increase by 4 units every 3 days 2
• If hypoglycemia occurs without clear cause: Reduce dose by 10-20% immediately 2

Monitoring Requirements

Daily fasting blood glucose monitoring is essential during the conversion and titration phase. 2 Increase the frequency of blood glucose monitoring during any insulin regimen change to detect both hypoglycemia and hyperglycemia. 1

Expected Clinical Outcomes

Insulin glargine provides more consistent 24-hour basal coverage with a flatter time-action profile compared to NPH insulin. 3 Meta-analyses demonstrate that insulin glargine reduces overall symptomatic hypoglycemia by 11% and nocturnal hypoglycemia by 26% compared to NPH insulin in type 2 diabetes patients. 4 Severe nocturnal hypoglycemia risk is reduced by 59% with insulin glargine versus NPH. 4

Critical Pitfall to Avoid

Do not assume a 1:1 conversion ratio without clarifying the NPH dosing schedule. 1 The FDA label explicitly distinguishes between once-daily NPH (1:1 conversion) and twice-daily NPH (80% conversion), and using the wrong ratio increases hypoglycemia or hyperglycemia risk. 1