Give with meals. Used for bolus dosing and correction scales.
Short-Acting
Regular (Humulin R, Novolin R)
30โ60 min
2โ4 h
6โ8 h
Used in IV drips (DKA). Only insulin safe for IV use.
Intermediate
NPH (Humulin N, Novolin N)
1โ2 h
4โ12 h
12โ18 h
Cloudy vial. Useful for steroid-induced hyperglycemia. Must be resuspended.
Long-Acting
Glargine (Lantus, Basaglar), Detemir (Levemir)
1โ2 h
Peakless
20โ24 h
Basal insulin of choice. Give once daily (glargine) or BID (detemir). Do NOT mix.
Ultra-Long
Degludec (Tresiba)
1 h
Peakless
42 h
Flexible dosing window. Lowest hypoglycemia risk among basals.
Concentrated
U-500 Regular
30 min
4โ8 h
12โ24 h
5x concentration of U-100. For severe insulin resistance (>200 units/day). High error risk -requires dedicated syringe.
Inpatient Basal-Bolus Protocol
Goal: Mimic physiologic insulin secretion. Basal covers fasting needs. Bolus covers meals. Correction fixes hyperglycemia. Target BG 140โ180 mg/dL for most ICU and non-ICU patients.
1
Calculate Total Daily Dose (TDD): 0.3โ0.5 units/kg/day. Start 0.3 units/kg for elderly, CKD (GFR < 30), hepatic impairment, or malnourished. Start 0.5 units/kg for insulin-resistant, obese, or steroid-treated patients.
2
Split TDD: 50% as basal (glargine once daily, usually at bedtime) + 50% as bolus (divided equally into 3 pre-meal doses of rapid-acting insulin).
3
Add correction scale: Give correction dose ON TOP of scheduled mealtime bolus based on pre-meal BG. Use low/medium/high scale based on insulin sensitivity (see table below).
4
Reassess daily: If BG consistently > 180 mg/dL, increase TDD by 10โ20%. If hypoglycemia occurs, decrease TDD by 20%. Adjust basal vs bolus based on fasting vs post-meal patterns.
Correction Scale (Sliding Scale Add-On)
Low scale: insulin-sensitive, elderly, CKD, hepatic. Medium scale: most patients. High scale: insulin-resistant, obese, on steroids, TDD > 80 units.
Blood Glucose (mg/dL)
Low Dose
Medium Dose
High Dose
150โ199
1 unit
2 units
3 units
200โ249
2 units
3 units
5 units
250โ299
3 units
5 units
7 units
300โ349
4 units
7 units
9 units
> 350
5 units + notify MD
8 units + notify MD
11 units + notify MD
Who Gets Which Scale?
The correction scale is NOT one-size-fits-all. Choosing the wrong scale causes hypoglycemia (too aggressive) or persistent hyperglycemia (too conservative). Match the scale to the patient's insulin sensitivity.
May still need even MORE. If BG stays > 300 on high scale, increase correction by 50% or add standing bolus doses.
Steroid-Induced Hyperglycemia -Special Protocol
Steroids cause the WORST inpatient hyperglycemia. Prednisone 40 mg can push BG to 400+ in diabetics. Most steroid hyperglycemia peaks 8โ12 hours after the dose (afternoon/evening for AM steroids). Standard sliding scales are often insufficient.
1
Always use HIGH-DOSE correction scale for any patient on โฅ 20 mg prednisone equivalent (or dexamethasone โฅ 4 mg, methylprednisolone โฅ 16 mg, hydrocortisone โฅ 80 mg).
2
Add NPH insulin with AM steroids: NPH peaks at 4โ12h, matching the steroid-induced glucose rise. Start at 0.1 units per mg of prednisone (e.g., prednisone 40 mg โ NPH 4 units with AM dose). Titrate aggressively -most patients need 0.2โ0.4 units/mg.
3
For dexamethasone (long-acting steroid): Hyperglycemia lasts 24โ36h. Use glargine (not NPH) since dex effect is longer. Increase basal insulin by 20โ40%. High-dose correction scale around the clock.
4
For pulse-dose steroids (methylprednisolone 1g/day): These patients WILL have BG 300โ500+. Start insulin drip protocol if BG > 300 ร 2 consecutive checks. Regular insulin drip 0.05โ0.1 units/kg/hr. BG checks q2h.
5
When tapering steroids โ taper insulin proportionally. As prednisone decreases, reduce NPH/correction scale. Failure to reduce insulin during steroid taper = hypoglycemia. Match insulin to current steroid dose daily.
Steroid
Equivalent Dose
Duration of BG Effect
Insulin Strategy
Prednisone (Deltasone) / Prednisolone (Orapred)
40 mg PO daily
12โ16h (peaks afternoon)
NPH with AM dose. Start 0.1 units/mg, titrate to 0.2โ0.4 units/mg. High-dose correction.
Methylprednisolone (Solu-Medrol)
32 mg IV daily
12โ18h
NPH or increase basal 20%. High-dose correction. If pulse dose (1g) โ insulin drip.
Dexamethasone (Decadron)
6 mg PO/IV daily
24โ36h (long-acting)
Increase glargine 20โ40%. High-dose correction around the clock. NPH won't cover -too short.
Hydrocortisone (Solu-Cortef)
80 mg IV daily
8โ12h per dose
If q8h dosing โ moderate hyperglycemia. Medium or high scale. Add NPH 2โ4 units per dose if BG > 250.
Non-diabetic on steroids? Up to 50% of patients on high-dose steroids develop new hyperglycemia. Check BG at least QID (before meals + bedtime). If BG > 180 ร 2 โ start correction scale. Many will need scheduled insulin.
Diabetic on steroids? Their home insulin is NEVER enough. Increase TDD by 30โ50% immediately when starting steroids. Don't wait for BG to spiral. Proactive dosing prevents glucose roller-coasters.
The #1 mistake: Using sliding scale ALONE for steroid patients. Correction-only dosing chases glucose after it's already sky-high. These patients need scheduled NPH or increased basal insulin PLUS high-dose correction scale.
DKA Insulin Drip Protocol
Do NOT start insulin if Kโบ < 3.5 mEq/L. Insulin drives Kโบ intracellularly and will cause fatal arrhythmia. Replete potassium first.
1
Check Kโบ BEFORE insulin: If Kโบ < 3.5 โ hold insulin, replete with 20โ40 mEq/hr KCl IV. Recheck in 1โ2 hours. Do NOT proceed until Kโบ โฅ 3.5.
2
Start regular insulin drip: 0.1 units/kg/hr continuous IV infusion. No initial bolus preferred (ADA 2026). Only regular insulin can be given IV.
3
Check BG hourly. Target BG drop: 50โ70 mg/dL per hour. If BG not dropping by โฅ 50 mg/dL/hr, double the drip rate. If dropping > 100 mg/dL/hr, halve the rate.
4
When BG < 200 mg/dL: Start D5 ยฝNS and reduce insulin drip to 0.02โ0.05 units/kg/hr. Continue drip until anion gap closes -NOT just until BG normalizes.
5
Transition to SQ insulin when ALL met: BG < 200 AND anion gap โค 12 AND bicarb โฅ 15 AND pH > 7.3. Give long-acting SQ insulin (glargine 0.25 units/kg) 2 hours BEFORE stopping drip to prevent rebound DKA.
Hypoglycemia Protocol
BG < 70 mg/dL (alert, able to eat): Give 15g fast-acting carbohydrates -4 oz juice, 4 glucose tabs, or 1 tbsp honey. Recheck BG in 15 minutes. Repeat if still < 70. Follow with complex carb/protein snack once BG > 80.
BG < 50 mg/dL or unable to eat: D50 25 mL IV push (12.5 g dextrose). Flush line. Recheck BG in 15 minutes. May repeat once. Start D10 drip if recurrent.
BG < 40 mg/dL or altered mental status: D50 50 mL IV push (25 g dextrose). If no IV access โ glucagon 1 mg IM/SQ. Position patient on side (glucagon causes nausea). Recheck BG q15 min.
After any episode: Hold ALL scheduled insulin doses. Investigate cause (missed meal, renal decline, medication error, sepsis). Reduce TDD by 20โ40%. Document and notify attending.
Key Clinical Pearls
Never use sliding scale alone -always pair correction insulin with a scheduled basal insulin. Sliding scale monotherapy leads to roller-coaster glucose and worse outcomes.
NPO patients still need basal insulin -reduce basal dose by 20โ50% but do NOT hold entirely. Basal insulin suppresses hepatic glucose output and prevents DKA in type 1 diabetics.
Steroid-induced hyperglycemia peaks in the afternoon -use NPH insulin with morning steroids (onset matches steroid-induced glucose rise). Dose: 0.1 units per mg of prednisone equivalent.
TPN patients: Add regular insulin directly to TPN bag at 0.1 units per gram of dextrose as starting dose. Titrate based on BG monitoring q6h.
Renal adjustment: Reduce TDD by 25% if GFR 10โ30 mL/min. Reduce TDD by 50% if GFR < 10 or on dialysis. Insulin clearance is markedly reduced in advanced CKD.
Always check Kโบ before starting insulin in any clinical setting -insulin shifts potassium intracellularly. This applies to DKA, hyperkalemia treatment, and routine dosing in CKD patients.
Insulin stacking: Rapid-acting insulin lasts 3โ5 hours. Avoid re-dosing correction insulin within 3 hours to prevent hypoglycemia from dose overlap.
Transition from drip to SQ: The 2-hour overlap is critical. Stopping the drip without SQ coverage causes rebound hyperglycemia/ketosis within 1โ2 hours.
๐งฎ Insulin Calculator
Method 1 -From Sliding Scale Usage
Add up all sliding scale insulin given in the past 24h.
Method 2 -Weight-Based (Insulin-Naive)
For patients not previously on insulin or no sliding scale data available.
Scenario
Recommendation
Patient eating normally
Full basal-bolus-correction: 50% basal (glargine QHS) + 50% nutritional (lispro AC meals) + correction scale
NPO
Continue basal (reduce 20โ50% if concerned). Hold nutritional. Correction-only q6h. Never hold basal completely in Type 1.
Tube feeds (continuous)
Basal (glargine) + correction q6h. Or NPH q12h + correction. Or 70/30 insulin q12h.
On steroids
โ TDD by 20โ40%. Steroids cause afternoon/evening hyperglycemia โ increase lunch and dinner doses more than basal.
Transitioning from drip
24h drip total ร 80% = TDD. Split 50/50. Give SubQ basal 2โ4h BEFORE stopping drip.
Correction factor
1800 รท TDD = how many mg/dL 1 unit drops glucose.