What is the equivalent dose of Lantus (insulin glargine) for a 36-year-old patient taking 10 units of Novolin (human insulin) per day?

Equivalent Lantus Dosing for Novolin Conversion

For a 36-year-old patient switching from 10 units of Novolin to Lantus, start with 10 units of Lantus once daily at the same time each day. The conversion is unit-for-unit when transitioning from NPH (Novolin N) or regular insulin (Novolin R) to insulin glargine 1, 2.

Conversion Protocol

If switching from Novolin N (NPH):

• Convert unit-for-unit: 10 units Novolin N → 10 units Lantus once daily 1, 2
• Administer Lantus at bedtime or the same time the NPH was given 1
• Lantus provides more stable 24-hour coverage with reduced nocturnal hypoglycemia risk compared to NPH 3, 4

If switching from Novolin R (regular insulin) used as basal coverage:

• Start with 10 units Lantus once daily 1
• Note that regular insulin is typically used for mealtime coverage, not basal needs 1
• If the patient was using Novolin R for both basal and prandial coverage, the regimen needs restructuring with Lantus for basal and rapid-acting insulin for meals 1

Titration After Conversion

Adjust the Lantus dose based on fasting blood glucose:

• Increase by 2 units every 3 days if fasting glucose is 140-179 mg/dL 1, 5, 2
• Increase by 4 units every 3 days if fasting glucose is ≥180 mg/dL 1, 5
• Target fasting glucose: 80-130 mg/dL 1, 5
• Reduce dose by 10-20% if hypoglycemia occurs without clear cause 1

Critical Monitoring Requirements

During the first 2-4 weeks after conversion:

• Check fasting blood glucose daily to guide titration 1, 5
• Monitor for hypoglycemia, especially nocturnal episodes, as Lantus has a flatter profile than NPH 3, 4
• The risk of nocturnal hypoglycemia is reduced by 26% with Lantus compared to NPH, but vigilance is still required 4

Important Considerations

Pharmacokinetic differences:

• Lantus provides relatively constant basal insulin over 24 hours with no pronounced peak, unlike NPH which peaks 4-8 hours after injection 3, 2
• This flatter profile means the 10-unit starting dose is appropriate and safe 3, 2

When to escalate beyond initial dose:

• If fasting glucose remains elevated after 3-4 days on 10 units, begin systematic titration as outlined above 1, 5
• Continue metformin and other oral agents unless contraindicated 1, 6
• When Lantus exceeds 0.5 units/kg/day (approximately 18 units for a 36 kg patient, or more realistically 35-40 units for an average-weight adult), consider adding prandial insulin rather than continuing to escalate basal insulin alone 1, 2

Common Pitfalls to Avoid

• Do not reduce the initial dose below 10 units without clinical justification (elderly, renal impairment, recurrent hypoglycemia) 1, 7
• Do not delay titration if fasting glucose remains above target—adjust every 3 days as needed 1, 5
• Do not mix Lantus with other insulins due to its low pH formulation 1
• Do not continue escalating Lantus beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia with prandial insulin 1, 2