Starting Basal Insulin in Primary Care: A Simple, Safe Workflow for NPs

Are you nervous to start insulin? I was too. Insulin therapy is highly individualized, but this step-by-step will help you start confidently and safely.

When I Consider Insulin

Start insulin up front or add it when any of the following are true:

• New diagnosis with A1c ≥10%

• Severe hyperglycemia: fasting >250 mg/dL or random >300 mg/dL

• A1c >9% with ketonuria or unintentional weight loss

• Known diabetes not controlled on oral agents and/or GLP-1 therapy

Always address dehydration, infection, steroid exposure, and adherence first.

First Step: Basal Insulin

Basal insulin targets overnight/fasting hyperglycemia and is the simplest place to start.

Common choices (pick based on coverage):

• Insulin glargine: Basaglar, Lantus, Rezvoglar, Semglee, Toujeo

• NPH (OTC options): Humulin N, Novolin N

Glargine vs NPH: similar A1c effect. Glargine generally has less nocturnal hypoglycemia but often higher cost.

How I Start (Dosing)

Two acceptable approaches; choose one and be consistent.

• Fixed start (my default): 10 units subQ at bedtime
  Easy, safe, memorable for patients and staff.

• Weight-based: 0.2 units/kg once daily (usually lands close to 10–20u)

Keep other glucose-lowering meds the same unless there’s a reason to adjust.

How I Titrate (the “3 & 3 Rule”)

Goal: fasting glucose <150 mg/dL (you can personalize to 80–130 if you want tighter ADA targets).

1. Start 10u nightly.

2. Patient checks fasting glucose every morning.

3. Increase by 3 units every 3 days until fasting is at goal.

Example

• Mon AM 200 → continue 10u Mon night

• Tue AM 190 → 10u Tue night

• Wed AM 170 → 10u Wed night

• Thu AM 180 → increase to 13u Thu night

• Continue increases q3 days until fasting <150.

Follow-up: 2–4 weeks (sooner if lows or rapid uptitration).

When I Split the Dose

If bedtime dose reaches >50–60 units, I often split to BID for smoother coverage:

• Example: 60u nightly → 30u AM + 30u PM.

Safety & Counseling (copy/paste for your portal)

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

• Driving/exercise: Check before driving or prolonged activity; carry glucose source.

• Sick day rules: Continue basal; hydrate; check more often; call for persistent BG >300, ketones, vomiting, or signs of DKA.

• Injection basics: Rotate sites (abdomen, thigh, arm), new needle each use, store pens per label.

• Bedtime snacks: Not mandatory; personalize if nocturnal lows occur.

Supplies to Prescribe

• Basal insulin pen(s)

• Pen needles (e.g., 4 mm), qty to cover daily use + extras

• Glucose meter, strips, lancets

• Hypoglycemia rescue: glucose tabs/gel; glucagon for patients at risk of severe lows

EMR SmartPhrase (feel free to steal)

Plan—Basal Start: Begin insulin glargine 10 units SQ nightly. Check fasting BG daily; increase by 3 units every 3 days until fasting <150 (unless BG <80 or symptomatic). Educated on injection technique, site rotation, hypoglycemia (15-15 rule), and sick-day management. Follow-up 2–4 weeks or sooner if lows. Consider BID split if dose >50–60u.

Pearls

• Glargine often = fewer nocturnal lows; NPH is cheaper/OTC and fine if used thoughtfully.

• Don’t wait months to adjust—titrate weekly using home logs or portal messages.

• Watch for steroid bursts, missed doses, and late-night snacking patterns when fasting sugars won’t budge.

• If fasting normal but A1c remains high, you’re seeing post-prandial hyperglycemia → consider adding mealtime insulin (stay tuned for next week’s post).

Quick Disclaimers

Education only; not medical advice. Use your clinical judgment, local protocols, and current guidelines. Screen for T1DM/DKA when appropriate (ketones, weight loss, autoimmune history).

Have questions or cases? [email protected]  or DM me on social.
Want 1:1 help building insulin workflows for your clinic? Mentorship spots are open—email me to book a free 15-minute call.

Next week: how I add mealtime insulin (carb-ratio vs fixed doses, correction scales, and hypoglycemia prevention).