What is the appropriate starting dose of insulin glargine (Lantus) for a 182‑lb (≈83‑kg) adult male?

Lantus Dosing for an 83-kg (182-lb) Adult Male

For an 83-kg adult male with type 2 diabetes who is insulin-naïve, start Lantus at 10 units once daily or use 0.1–0.2 units/kg/day (8–17 units), administered at the same time each day. 1, 2

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Initial Dosing Strategy

• Standard starting dose: Begin with 10 units once daily for most insulin-naïve patients with type 2 diabetes, or calculate 0.1–0.2 units/kg/day (which equals 8–17 units for an 83-kg man). 1, 2
• Severe hyperglycemia (A1C ≥9%, fasting glucose ≥300 mg/dL): Consider a higher starting dose of 0.3–0.4 units/kg/day (25–33 units) to achieve targets faster. 1
• Continue metformin at maximum tolerated dose (up to 2000–2550 mg/day) unless contraindicated, as this combination reduces insulin requirements and weight gain. 1

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Titration Protocol

• Increase by 2 units every 3 days if fasting glucose is 140–179 mg/dL. 1
• Increase by 4 units every 3 days if fasting glucose is ≥180 mg/dL. 1
• Target fasting glucose: 80–130 mg/dL. 1
• If hypoglycemia occurs (glucose <70 mg/dL), reduce the dose by 10–20% immediately. 1

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Critical Threshold: When to Stop Escalating Basal Insulin

• When Lantus exceeds 0.5 units/kg/day (≈42 units for an 83-kg man) and approaches 1.0 units/kg/day (≈83 units), add prandial insulin rather than continuing to escalate basal insulin alone. 1
• Signs of "overbasalization" include:
  • Basal dose >0.5 units/kg/day 1
  • Bedtime-to-morning glucose drop ≥50 mg/dL 1
  • Hypoglycemia episodes 1
  • High glucose variability 1

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Administration Guidelines

• Inject subcutaneously into the abdomen, thigh, or deltoid once daily at the same time each day. 2
• Rotate injection sites within the same region to prevent lipodystrophy. 2
• Do not mix or dilute Lantus with any other insulin or solution. 2
• Do not administer intravenously or via an insulin pump. 2

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Monitoring Requirements

• Check fasting blood glucose daily during titration. 1
• Reassess every 3 days during active dose adjustment. 1
• Measure HbA1c every 3 months once stable. 1

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Common Pitfalls to Avoid

• Do not delay insulin initiation in patients not achieving glycemic goals with oral medications alone—this prolongs hyperglycemia exposure and increases complication risk. 1
• Do not discontinue metformin when starting insulin unless contraindicated—this leads to higher insulin requirements and more weight gain. 1
• Do not continue escalating Lantus beyond 0.5–1.0 units/kg/day without addressing postprandial hyperglycemia—this causes overbasalization with increased hypoglycemia risk and suboptimal control. 1

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When to Add Prandial Insulin

• Add prandial insulin if:
  • Fasting glucose is controlled (80–130 mg/dL) but HbA1c remains above target after 3–6 months. 1
  • Basal insulin dose approaches 0.5–1.0 units/kg/day without achieving HbA1c goal. 1
• 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 every 3 days based on 2-hour postprandial glucose readings. 1