What is the initial dosing regimen for Lantus Solostar (insulin glargine) 100 units/mL in a diabetic patient with potential impaired renal function and/or hepatic function?

How to Prescribe Lantus SoloStar Insulin 100 units/mL

Initial Dosing for Type 2 Diabetes

Start with 10 units once daily OR 0.1-0.2 units/kg body weight, administered at the same time each day (morning or bedtime). 1, 2

• For patients with mild-to-moderate hyperglycemia (HbA1c <9%), use 10 units once daily as a fixed starting dose 1
• For patients with more severe hyperglycemia (HbA1c ≥9% or blood glucose ≥300 mg/dL), consider higher starting doses of 0.3-0.4 units/kg/day 1, 2
• Continue metformin at maximum tolerated dose (up to 2000-2550 mg daily) unless contraindicated, as this combination provides superior glycemic control with reduced insulin requirements 1, 3
• Consider discontinuing sulfonylureas when starting insulin to reduce hypoglycemia risk 1

Initial Dosing for Type 1 Diabetes

Start with 0.5 units/kg/day as total daily dose, giving approximately 50% as Lantus (basal) once daily and 50% as rapid-acting insulin (prandial) divided among meals. 1, 2

• Total daily insulin requirements typically range from 0.4-1.0 units/kg/day for type 1 diabetes 1, 2
• Higher doses are required during puberty, pregnancy, and medical illness 2
• Lantus provides basal insulin coverage only; rapid-acting insulin is required at mealtimes to control postprandial glucose 1

Dose Titration Algorithm

Increase the dose by 2-4 units every 3 days until fasting blood glucose reaches 80-130 mg/dL. 1, 4

Specific Titration Schedule:

• If fasting glucose is 140-179 mg/dL: increase by 2 units every 3 days 1
• If fasting glucose is ≥180 mg/dL: increase by 4 units every 3 days 1
• If hypoglycemia occurs without clear cause: reduce dose by 10-20% immediately 1
• If more than 2 fasting glucose values per week are <80 mg/dL: decrease by 2 units 1

Patient Self-Titration Option:

• Patients can be taught to self-titrate by adding 2 units every 3 days if fasting glucose remains above target, in the absence of blood glucose <72 mg/dL 4
• Patient-managed titration achieves greater HbA1c reductions (-1.22% vs -1.08%) compared to clinic-managed titration 4

Critical Threshold: When to Stop Escalating Basal Insulin

When Lantus exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add prandial insulin or a GLP-1 receptor agonist rather than continuing to escalate basal insulin alone. 1, 3

Clinical Signals of "Overbasalization":

• Basal insulin dose >0.5 units/kg/day 1
• Bedtime-to-morning glucose differential ≥50 mg/dL 1
• Episodes of hypoglycemia 1
• High glucose variability throughout the day 1
• HbA1c remains elevated despite controlled fasting glucose 1

Adding Prandial Insulin:

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

Administration Guidelines

Administer Lantus subcutaneously once daily at the same time each day, either morning or bedtime. 5

• Morning or bedtime administration achieves equivalent glycemic control with similar hypoglycemia rates 5
• Do not dilute or mix Lantus with any other insulin or solution due to its low pH 1
• Inject subcutaneously in the abdomen, thigh, or upper arm with proper site rotation 1
• The SoloStar pen delivers doses accurately from 1-80 units in 1-unit increments 6

Special Population Adjustments

Renal Impairment:

• CKD Stage 5 with Type 2 diabetes: reduce total daily insulin dose by 50% 7, 2
• CKD Stage 5 with Type 1 diabetes: reduce total daily insulin dose by 35-40% 2
• For eGFR <45 mL/min/1.73 m²: titrate conservatively and monitor closely for hypoglycemia 3
• Start with 0.1-0.2 units/kg/day for patients with severe renal impairment 7

Hepatic Impairment:

• Lower insulin doses are required; titrate per clinical response and monitor closely for hypoglycemia 3

Elderly Patients (>65 years):

• Use lower starting doses of 0.1-0.25 units/kg/day to prevent hypoglycemia 1
• Consider less aggressive HbA1c targets (<8.0% rather than <7.0%) for those with multiple comorbidities or limited life expectancy 1

Hospitalized Patients:

• For insulin-naive or low-dose insulin patients: start with 0.3-0.5 units/kg/day total daily dose, giving half as basal insulin 1
• For patients on high-dose home insulin (≥0.6 units/kg/day): reduce total daily dose by 20% upon admission to prevent hypoglycemia 1, 2

Steroid-Induced Hyperglycemia:

• Consider NPH insulin instead of Lantus for steroid-induced hyperglycemia, as NPH's intermediate-acting profile (peaks at 4-6 hours) aligns with glucocorticoid-induced hyperglycemia 7
• If using Lantus, increase prandial and correction insulin by 40-60% in addition to basal insulin 1
• Reduce insulin doses by 10-20% with each significant steroid dose reduction 7

Monitoring Requirements

Daily fasting blood glucose monitoring is essential during the titration phase. 1

• Check fasting glucose every morning and adjust dose every 3 days during active titration 1
• Reassess adequacy of insulin dose at every clinical visit, looking for signs of overbasalization 1
• Check HbA1c every 3 months during intensive titration 1
• Once stable, reassess every 3-6 months to avoid therapeutic inertia 1

Common Pitfalls to Avoid

Never delay insulin initiation in patients not achieving glycemic goals with oral medications alone, as this prolongs hyperglycemia exposure and increases complication risk 1, 3

Never discontinue metformin when starting insulin unless contraindicated, as this leads to higher insulin requirements and more weight gain 1, 3

Never continue escalating 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 1, 3

Never use sliding scale insulin as monotherapy, as scheduled basal insulin (with correction doses as adjunct only) is superior 1

Never give rapid-acting insulin at bedtime to correct hyperglycemia, as this significantly increases nocturnal hypoglycemia risk 1

Patient Education Essentials

Provide comprehensive education on: 1

• Proper insulin injection technique and site rotation
• Self-monitoring of blood glucose
• Recognition and treatment of hypoglycemia (treat any glucose <70 mg/dL with 15 grams of fast-acting carbohydrate)
• "Sick day" management rules
• Insulin storage and handling (store unopened pens in refrigerator; opened pens can be kept at room temperature for up to 28 days)

Expected Outcomes

With appropriate basal insulin therapy and titration: 1

• HbA1c reduction of 1.5-2.0% from baseline is achievable over 3-6 months
• 30-33% of patients reach HbA1c ≤7% without nocturnal hypoglycemia 4, 8
• Lantus reduces risk of nocturnal hypoglycemia by 26% compared to NPH insulin 8
• Severe hypoglycemia risk is reduced by 46% compared to NPH insulin 8