What is the recommended treatment regimen for a patient with diabetes requiring Humulin R (Regular Insulin)?

Humulin R (Regular Insulin) Treatment Regimen

Initial Dosing for Type 1 Diabetes

For newly diagnosed Type 1 diabetes, start with a total daily insulin dose of 0.5 units/kg/day, divided approximately 50% as basal insulin and 50% as prandial insulin (Humulin R) distributed across three meals. 1, 2

• Total daily insulin requirements typically range from 0.4 to 1.0 units/kg/day for Type 1 diabetes patients 1
• Humulin R should be administered 30-45 minutes before meals to match its onset of action, which differs from rapid-acting analogs that can be given 0-15 minutes before eating 2
• Higher doses (up to 1.0 units/kg/day or more) are required during puberty, pregnancy, and acute illness 1
• Patients in the "honeymoon phase" with residual beta-cell function may require lower doses of 0.2-0.6 units/kg/day 1

Initial Dosing for Type 2 Diabetes

For Type 2 diabetes patients requiring insulin, begin with basal insulin at 10 units once daily or 0.1-0.2 units/kg/day, continuing metformin unless contraindicated. 1, 3

• For severe hyperglycemia (HbA1c ≥10%, blood glucose ≥300-350 mg/dL, or symptomatic/catabolic features), immediately initiate basal-bolus therapy with 0.3-0.5 units/kg/day total daily dose, divided approximately 50% basal and 50% prandial (Humulin R) 1, 3
• Humulin R can be used as prandial coverage, starting with 4 units before each meal or 10% of the basal dose before the largest meal 1
• Continue metformin when initiating insulin therapy, as it reduces weight gain, lowers total insulin requirements, and decreases hypoglycemia risk 2, 4

Dose Titration Protocol

Increase basal insulin by 2 units every 3 days if fasting glucose is 140-179 mg/dL, or by 4 units every 3 days if fasting glucose is ≥180 mg/dL, until reaching target of 80-130 mg/dL. 1

• For Humulin R (prandial insulin), titrate by 1-2 units or 10-15% every 3 days based on pre-meal and 2-hour postprandial glucose readings 1
• If hypoglycemia occurs, determine the cause and reduce the corresponding dose by 10-20% immediately 1
• Daily fasting blood glucose monitoring is essential during titration, with additional pre-meal and bedtime testing 5

Critical Threshold: Recognizing Overbasalization

When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add or intensify prandial insulin (Humulin R) rather than continuing to escalate basal insulin alone. 1

• Clinical signals of overbasalization include: basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability 1
• Blood glucose levels in the 200s mg/dL indicate both inadequate basal coverage AND postprandial excursions requiring mealtime insulin 1

Hospitalized Patients

For non-critically ill hospitalized patients who are insulin-naive, start with 0.3-0.5 units/kg/day total daily dose, giving half as basal insulin and half as Humulin R divided among meals. 1

• For patients on high-dose home insulin (≥0.6 units/kg/day), reduce the total daily dose by 20% upon admission to prevent hypoglycemia 1
• Lower doses (0.1-0.25 units/kg/day) are recommended for high-risk patients: elderly (>65 years), those with renal failure, or poor oral intake 1
• Scheduled basal-bolus regimens are superior to sliding scale insulin monotherapy 1

Timing and Administration

Humulin R must be administered 30-45 minutes before meals, not immediately before or after eating, to effectively manage postprandial glucose levels. 1

• This differs significantly from rapid-acting insulin analogs (lispro, aspart, glulisine) which are given 0-15 minutes before meals 2
• The peak action of Humulin R occurs 2-4 hours after injection, requiring careful meal timing coordination 5
• Humulin R should not be mixed with insulin glargine due to pH incompatibility 1

Essential Patient Education

Teach patients the "Rule of 15" for hypoglycemia: treat with 15 grams of fast-acting carbohydrates, recheck glucose in 15 minutes, and repeat if needed. 5

• Educate on hypoglycemia recognition: shakiness, sweating, confusion, rapid heartbeat, and hunger 5
• Proper injection technique and site rotation must be taught to prevent lipodystrophy and ensure consistent absorption 5, 2
• Patients should understand that Humulin R requires 30-45 minute lead time before meals, unlike rapid-acting analogs 1
• Provide education on sick day rules: never stop insulin and check glucose more frequently during illness 3

Common Pitfalls to Avoid

Do not delay insulin initiation in patients not achieving glycemic goals with oral medications—this prolongs exposure to hyperglycemia and increases complication risk. 1

• Avoid continuing to escalate basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this leads to suboptimal control and increased hypoglycemia risk 1
• Do not abruptly discontinue oral medications when starting insulin; continue metformin unless contraindicated 2, 4
• Avoid relying solely on sliding scale insulin in hospitalized patients—scheduled basal-bolus regimens are superior 6, 1
• Do not use Humulin R immediately before meals like rapid-acting analogs; the 30-45 minute lead time is critical 1

Special Clinical Situations

For patients on corticosteroids, increase prandial and correction insulin (Humulin R) by 40-60% or more in addition to basal insulin adjustments. 1

• During perioperative periods, reduce insulin dose by approximately 25% the evening before surgery to achieve target glucose with decreased hypoglycemia risk 1
• For patients with acute illness and poor oral intake, use lower doses (0.1-0.25 units/kg/day) to prevent hypoglycemia 1