Which long‑acting insulin and starting dose should I prescribe for an obese adult with an A1C of 11.7% and severe systolic hypertension but otherwise normal temperature, heart rate, renal function, and oxygen saturation?

Insulin Initiation for Severe Uncontrolled Type 2 Diabetes

Start insulin glargine (Lantus) at 20 units once daily at bedtime (approximately 0.15 units/kg for this 259-lb patient) and add rapid-acting insulin (lispro or aspart) at 6 units before each of the three largest meals, while continuing metformin at maximum tolerated dose. This patient's A1C of 11.7% with severe systolic hypertension demands immediate basal-bolus insulin therapy rather than basal insulin alone. 1

Immediate Medication Regimen

Basal Insulin (Lantus/Glargine)

• Initial dose: 20 units subcutaneously once daily at bedtime (approximately 0.15–0.17 units/kg for a 259-lb/117-kg patient). 1
• For patients with A1C ≥ 9% or glucose ≥ 300 mg/dL, guidelines recommend starting with 0.3–0.5 units/kg/day total insulin split between basal and prandial components; however, a more conservative initial basal dose of 0.15–0.2 units/kg reduces hypoglycemia risk during the titration phase. 1
• Administer at the same time each evening to maintain consistent 24-hour basal coverage. 1

Prandial Insulin (Lispro or Aspart)

• Initial dose: 6 units before each of the three largest meals (breakfast, lunch, dinner). 1
• This represents approximately 10% of a projected total daily dose of 60 units (20 U basal + 18 U prandial + titration room). 1
• Administer 0–15 minutes before meals (ideally immediately before eating) for optimal postprandial glucose control. 1

Foundation Therapy: Metformin

• Continue or initiate metformin at 1000 mg twice daily (2000 mg total) unless contraindicated by the patient's renal function (current GFR 141 mL/min indicates normal kidney function). 2
• Metformin reduces total insulin requirements by 20–30% and provides superior glycemic control compared with insulin alone. 1, 2
• Do not discontinue metformin when starting insulin; this combination is essential for minimizing insulin doses and limiting weight gain. 1, 2

Systematic Titration Protocol

Basal Insulin (Lantus) Titration

• Increase by 4 units every 3 days if fasting glucose remains ≥ 180 mg/dL. 1
• Increase by 2 units every 3 days if fasting glucose is 140–179 mg/dL. 1
• Target fasting glucose: 80–130 mg/dL. 1
• Stop basal escalation when the dose approaches 0.5 units/kg/day (approximately 58 units for this patient) without achieving targets; at this threshold, intensify prandial insulin rather than continuing basal increases to avoid "over-basalization." 1, 3

Prandial Insulin Titration

• Increase each meal dose by 1–2 units every 3 days based on the 2-hour postprandial glucose reading after that meal. 1
• Target postprandial glucose: < 180 mg/dL. 1
• If hypoglycemia (glucose < 70 mg/dL) occurs without an obvious cause, reduce the implicated dose by 10–20% immediately. 1

Correction (Supplemental) Insulin

• Add 2 units of rapid-acting insulin for pre-meal glucose > 250 mg/dL. 1
• Add 4 units for pre-meal glucose > 350 mg/dL. 1
• Correction doses must supplement—not replace—scheduled basal and prandial insulin. 1

Monitoring Requirements

• Daily fasting glucose to guide basal insulin adjustments. 1
• Pre-meal glucose before each meal to calculate correction doses. 1
• 2-hour postprandial glucose after each meal to assess prandial insulin adequacy. 1
• Bedtime glucose to evaluate overall daily pattern. 1
• Reassess insulin doses every 3 days during active titration. 1
• A1C every 3 months until stable control is achieved. 1

Blood Pressure Management Considerations

• This patient's BP 170/72 mm Hg represents severe systolic hypertension requiring immediate antihypertensive therapy in addition to glycemic management. While not the primary focus of this insulin question, uncontrolled hypertension significantly increases cardiovascular risk in diabetes.
• Insulin therapy itself does not directly worsen blood pressure, but weight gain from insulin intensification can indirectly affect BP control.

Expected Clinical Outcomes

• A1C reduction of 3–4% (from 11.7% to approximately 7.7–8.7%) is achievable within 3–6 months with intensive basal-bolus insulin therapy combined with metformin. 1
• Approximately 68% of patients achieve mean glucose < 140 mg/dL with properly implemented basal-bolus therapy, compared with only 38% using inadequate insulin regimens. 1
• No increase in hypoglycemia incidence when basal-bolus regimens are correctly applied versus under-dosed insulin. 1

Critical Pitfalls to Avoid

• Do not delay insulin initiation in patients with A1C > 9%; prolonged severe hyperglycemia increases complication risk. 1, 2
• Never use sliding-scale insulin as monotherapy; correction doses must supplement scheduled basal and prandial insulin. 1
• Do not continue escalating basal insulin beyond 0.5–1.0 units/kg/day without addressing postprandial hyperglycemia; this leads to over-basalization with increased hypoglycemia risk and suboptimal control. 1, 3
• Do not discontinue metformin when starting insulin unless contraindicated; omission increases insulin requirements and worsens outcomes. 1, 2
• Never administer rapid-acting insulin at bedtime as a sole correction dose; this markedly raises nocturnal hypoglycemia risk. 1

Patient Education Essentials

• Hypoglycemia treatment: Consume 15 g fast-acting carbohydrate when glucose < 70 mg/dL, recheck in 15 minutes, and repeat if needed. 1
• Insulin injection technique and site rotation to prevent lipohypertrophy. 1
• Self-titration algorithm empowering the patient to adjust basal dose based on fasting glucose values. 1
• Sick-day management: Continue insulin even if oral intake is limited, check glucose every 4 hours, and maintain adequate hydration. 1
• Recognition of hyperglycemic symptoms and when to seek urgent care (glucose > 300 mg/dL with nausea/vomiting). 1

Alternative Insulin Options

Insulin Degludec (Tresiba)

• Degludec offers greater dosing flexibility with a duration of action exceeding 42 hours, allowing administration at varying times without loss of efficacy. 4, 5
• In clinical trials, degludec demonstrated non-inferiority to glargine for A1C reduction with significantly lower rates of nocturnal hypoglycemia. 4, 5
• Initial dosing: 10 units once daily (or 0.1–0.2 units/kg/day), titrated similarly to glargine. 4
• However, cardiovascular safety concerns were raised by FDA meta-analysis showing approximately 60% increase in cardiovascular events (myocardial infarction, stroke, cardiovascular death), though subsequent long-term trials have not confirmed this risk. 6
• Cost considerations: Degludec is typically more expensive than glargine and may not be covered by all insurance plans.

When to Consider Degludec

• Patients with erratic schedules who cannot inject at the same time daily. 4, 5
• Patients with recurrent nocturnal hypoglycemia on glargine despite dose adjustments. 5
• Patients requiring twice-daily basal insulin on glargine who might achieve once-daily dosing with degludec. 5

GLP-1 Receptor Agonist Consideration

• If basal insulin exceeds 0.5 units/kg/day (approximately 58 units) without achieving targets, consider adding a GLP-1 receptor agonist (e.g., semaglutide, dulaglutide) instead of further prandial insulin intensification. 1
• The basal insulin + GLP-1 RA combination provides comparable postprandial control with less hypoglycemia and weight loss rather than weight gain. 1
• However, for this patient's severe hyperglycemia (A1C 11.7%), immediate basal-bolus insulin is preferred to achieve rapid control; GLP-1 RA can be added later if needed. 1

Summary Algorithm

1. Start Lantus 20 units at bedtime + lispro/aspart 6 units before each meal + metformin 1000 mg twice daily. 1, 2
2. Check fasting glucose daily and 2-hour postprandial glucose after each meal. 1
3. Titrate basal insulin by 2–4 units every 3 days based on fasting glucose. 1
4. Titrate prandial insulin by 1–2 units every 3 days based on postprandial glucose. 1
5. Stop basal escalation at 0.5 units/kg/day (approximately 58 units); intensify prandial insulin instead. 1, 3
6. Reassess A1C in 3 months; expect reduction to approximately 7.7–8.7%. 1
7. Consider GLP-1 RA if basal insulin exceeds 0.5 units/kg/day without achieving targets. 1