Clinical PEARLS for Prescribing Insulin (Primary Care Edition)

We’ve spent the last couple of weeks building insulin regimens. Today: practical tips, tricks, and scripts to make prescribing insulin (and supplies) painless.

1) Know Your Concentrations & Containers

• Most insulins are U-100 (100 units/mL).

• Higher strengths (e.g., U-200 glargine/degludec, U-300 glargine, U-500 regular) are for very high daily doses—usually with endocrinology on board.

• Common package sizes

  • Vial: 10 mL → 1,000 units (U-100)

  • Pen pack: 5 pens × 3 mL each → 1,500 units total (U-100)

2) Put This On Every Rx

• “May change per insurance formulary.”

• Frequency of injections and testing (or it bounces back).

• For supplies: device name + compatible strips/lancets/pen needles + frequency.

3) Sample Insulin Prescriptions (copy/paste)

Vial + syringe example (basal start)

Rapid-acting add-on (meal dose)

4) Syringes & Pen Needles (what to choose)

Syringes (U-100):

• 0.3 mL = up to 30 units (best if doses <30 u)

• 0.5 mL = up to 50 units

• 1.0 mL = up to 100 units

Example: Patient takes 20 u BID → 0.3 mL syringe is perfect.

Pen needles: 31–33G, 4–6 mm length works for most adults (less painful, no pinch needed for many).

5) Quantity Math (so you don’t get callbacks)

• Daily dose × 30 = monthly units needed

• Compare to container totals to pick the right quantity.

Examples

• 40 u/day → 1,200 units/month → 2 vials (2 × 1,000 = 2,000 u) or 1 pen carton (1,500 u).

• 20 u BID (40 u/day) with pens → “Dispense 1 carton; RF 2.”

6) Don’t Forget the Testing/CGM Supplies

BGM kit

Many plans allow BID checks by default; some will cover QID for insulin-treated patients.

CGM options (verify coverage criteria)

• Freestyle Libre 14-day/2-week sensors; Libre 3 real-time

• Dexcom G6/G7
  Include: receiver/app, sensors, and transmitter (if applicable).

7) Patient Instructions That Prevent Calls

• Hypoglycemia plan (15-15 rule): 15 g fast carbs, recheck 15 min, repeat if <70.

• Injection timing: basal same time daily; rapid analogs 0–15 min before meals; regular ~30 min before.

• Site rotation (abdomen, thighs, upper arms; move 1–2 inches each time).

• Storage: unopened pens/vials in fridge; open pen typically room temp per label (check brand).

• Travel: keep a backup pen/vial and glucose tabs with you.

8) EMR SmartPhrase (toss this in your note/message)

Insulin/Supplies Plan: U-100 insulin prescribed. Starting dose 10 u QHS (or per regimen). Supplies ordered: [pen needles or syringes], meter/strips/lancets BID testing (increase if needed), or CGM if covered. Rx includes “may change per insurance formulary.” Patient instructed on injection technique, site rotation, hypoglycemia (15-15 rule), storage, and sharps disposal. Follow-up 2–4 weeks or sooner for BG <70 or persistent BG >300.

9) Pearls That Save Sanity

• Formulary swap language prevents 90% of pharmacy callbacks.

• If the nightly basal dose creeps >50–60 u, consider splitting to BID for smoother coverage.

• NPH is fine (and OTC) when cost is the barrier; teach bedtime snack and watch for nocturnal lows.

• Many patients on GLP-1s need less prandial insulin—titrate down to avoid lows.

• Put quantity math in your note so future you knows why you chose that amount.

Questions? Cases you want to sanity-check? [email protected]  or DM me on social.
Want personalized help building your clinic’s diabetes workflows? 1:1 mentorship spots are open—email me for a free 15-minute call.