What is the best starting dose for Lantis (insulin glargine) when transitioning a patient with type 2 diabetes away from sliding scale insulin?

Starting Dose for Lantus When Transitioning from Sliding Scale Insulin

Start with 10 units of Lantus once daily (or 0.1-0.2 units/kg body weight) administered at the same time each day, and completely discontinue sliding scale insulin as monotherapy. 1, 2

Why Sliding Scale Must Be Abandoned

Sliding scale insulin as the sole treatment is explicitly condemned by all major diabetes guidelines and should be immediately discontinued. 1, 3 A randomized controlled trial demonstrated that basal-bolus treatment improved glycemic control and reduced hospital complications compared to sliding scale insulin in general surgery patients with type 2 diabetes. 1

The fundamental problem with sliding scale monotherapy is that it treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations and poor glycemic control. 3 In comparative studies, only 38% of patients achieved mean blood glucose <140 mg/dL with sliding scale alone versus 68% with proper basal-bolus therapy, with no difference in hypoglycemia rates. 3

Initial Dosing Algorithm

For most patients with type 2 diabetes:

• Start with 10 units once daily if transitioning from oral medications or mild hyperglycemia 2, 4
• Use 0.1-0.2 units/kg/day for weight-based dosing (typically 7-14 units for a 70 kg patient) 2, 4
• Administer at the same time each day, typically at bedtime 2

For patients with severe hyperglycemia (A1C ≥9%, blood glucose ≥300-350 mg/dL):

• Consider higher starting doses of 0.3-0.5 units/kg/day as total daily insulin 2
• These patients likely require immediate basal-bolus therapy rather than basal insulin alone 2

Titration Protocol

Increase the Lantus dose systematically based on fasting glucose readings: 2

• If fasting glucose ≥180 mg/dL: increase by 4 units every 3 days
• If fasting glucose 140-179 mg/dL: increase by 2 units every 3 days
• Target fasting glucose: 80-130 mg/dL
• If hypoglycemia occurs, reduce dose by 10-20% immediately 2

Daily fasting blood glucose monitoring is essential during the titration phase. 2 Equip patients with self-titration algorithms based on self-monitoring, as this improves glycemic control compared to clinic-managed titration alone. 5

When to Add Prandial Insulin

Critical threshold to recognize: When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, adding prandial insulin becomes more appropriate than continuing to escalate basal insulin alone. 2

Clinical signals of "overbasalization" that indicate need for prandial insulin include: 2

• Basal dose >0.5 units/kg/day
• Bedtime-to-morning glucose differential ≥50 mg/dL
• Hypoglycemia episodes
• High glucose variability
• Fasting glucose at target but A1C remains elevated after 3-6 months

Starting prandial insulin: 2

• Begin with 4 units of rapid-acting insulin before the largest meal
• Alternatively, use 10% of the current basal dose
• Titrate by 1-2 units or 10-15% every 3 days based on postprandial glucose readings

Foundation Therapy Considerations

Continue metformin unless contraindicated when initiating or intensifying insulin therapy, as it reduces total insulin requirements and provides complementary glucose-lowering effects. 2 Consider continuing one additional non-insulin agent alongside basal insulin. 2

Common Pitfalls to Avoid

Never delay insulin initiation in patients not achieving glycemic goals with oral medications, as this prolongs exposure to hyperglycemia and increases complication risk. 2

Do not continue sliding scale as monotherapy even temporarily—the evidence is clear that scheduled basal insulin (with correction doses as adjunct only) is superior. 1, 3

Avoid continuing to escalate basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this leads to overbasalization with increased hypoglycemia risk and suboptimal control. 2

Do not wait longer than 3 days between basal insulin adjustments in stable patients, as this unnecessarily prolongs time to achieve glycemic targets. 2 The danger of under-adjusting is demonstrated by the finding that 75% of hospitalized patients who experienced hypoglycemia had no basal insulin dose adjustment before the next administration. 1

Acceptable Use of Correction Insulin

Sliding scale correction doses may be used as an adjunct to scheduled basal insulin, not as monotherapy. 3 If correction doses are frequently required, increase the scheduled basal insulin dose rather than continuing to rely on sliding scale corrections. 3