Adding Mealtime Insulin (Prandial) After Basal: A Simple NP Workflo

You got fasting glucose under control with basal insulin…but the A1c is still high or post-meal readings are spiking. Time to layer in prandial insulin.

When to add prandial insulin

• Fasting glucose is at goal but A1c remains above target

• Clear post-meal spikes on home logs or CGM

• High daytime readings tied to meals despite optimized basal/GLP-1/orals

Step 1 — Pick the insulin & timing

Rapid-acting analogs (preferred): aspart (Novolog/Fiasp), lispro (Humalog), glulisine (Apidra)

• Dose to start (pick one): 4–5 units OR 10% of total daily basal dose before the meal

• Timing: inject 0–15 minutes before eating (Fiasp can be right at the start of the meal)

Short-acting regular insulin:

• Dose to start (pick one): 4–6 units, 0.1 units/kg (max 10 units), OR 10% of basal dose before the meal

• Timing: 30 minutes before the meal

Start with one problem meal (e.g., lunch), not all three at once, unless hyperglycemia is severe.

Step 2 — Add prandial to other meals (if needed)

When another meal shows persistent post-prandial hyperglycemia, add 4 units before that meal (or mirror the initial approach that worked).

Step 3 — Titrate safely

For regular insulin already in use (titration by current dose):

• Using <10 units per dose → increase by 1 unit

• Using 11–20 units per dose → increase by 2 units

• Using >20 units per dose → increase by 3 units

For rapid-acting analogs (simple rule):

• If 2 of 3 days show 2-hour post-meal BG >180 mg/dL, ↑ that meal dose by 1 unit

• If post-meal <80 mg/dL or symptomatic lows, ↓ that meal dose by 1–2 units

Reassess every 1–2 weeks (or sooner if hypoglycemia).

Quick Examples

Example 1

• Basal: 30 units BID; fasting now <150 with no lows

• A1c still 9%; logs show lunch spikes

• Plan: Start aspart 4 units pre-lunch. Review logs in 1–2 weeks; titrate per rules above.

Example 2

• Six months later, dinner spikes appear

• Plan: Either ↑ pre-lunch from 4 → 5 units, and/or add pre-dinner 4 units depending on patterns and risk of lows.

Safety & Counseling 

• Hypoglycemia plan (15-15 rule): If BG <70 mg/dL, take 15 g fast carbs (4 oz juice or 3–4 glucose tabs), recheck in 15 min; repeat if still <70; eat a snack if the next meal is >1 hr away.

• Timing matters: regular insulin 30 min before, rapid-acting 0–15 min before meals.

• Hold or reduce the pre-meal dose if skipping a meal, eating far less, or pre-meal BG is <90 mg/dL.

• Sick day: keep basal; usually give prandial if eating; hydrate; check more often; call for persistent BG >300, ketones, vomiting, or signs of DKA.

• GLP-1 users: may need lower prandial doses; titrate cautiously.

• Documentation: record dose, timing, and any lows; message logs weekly during titration.

Supplies to Prescribe (if not already)

• Rapid-acting insulin pens, pen needles, and a sharps plan

• Meter/strips/lancets or CGM if covered

• Glucose tabs/gel; consider nasal glucagon for severe hypoglycemia risk

When Things Aren’t Working

• If fasting is perfect but daytime still high, you likely need more prandial, not more basal.

• If all meals spike, consider a small dose at each meal (e.g., 3–4 units) and titrate.

• Re-check steroids, infections, meal composition, and late-night snacking.

EMR SmartPhrase (steal this)

Plan—Add prandial insulin: Begin aspart __ units before [lunch/dinner] (or 10% of basal). Check post-meal BG ~2 hrs after; if >180 mg/dL on 2 of 3 days, increase by 1 unit for that meal. If BG <80 or symptomatic lows, decrease by 1–2 units. Continue basal as prescribed. Hypoglycemia and sick-day precautions reviewed. Follow-up/log review in 1–2 weeks.

Final Thoughts

Adding mealtime insulin doesn’t have to be scary. Start small, target the meal that’s causing trouble, and titrate methodically with close follow-up.

Have questions or want case-by-case help? [email protected]  or DM me on social.
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