Overview

Insulin is given subcutaneously at a 90-degree angle (45 degrees for thin clients) into rotating sites: the abdomen absorbs fastest, then arms, thighs, and buttocks (slowest). Rotate WITHIN the same anatomic region to prevent lipohypertrophy while keeping absorption predictable. When two insulins go in one syringe, draw up clear (regular) before cloudy (NPH) — 'clear before cloudy' — so the regular vial is never contaminated with NPH. Roll NPH gently between the palms to resuspend; never shake (it denatures protein and adds air). Opened vials last 28 days at room temperature; inject at room temperature to reduce pain and stabilize absorption. Do not massage after injecting — it speeds absorption unpredictably. For pens, hold the needle in the skin 10 seconds for the full dose. Only regular insulin may be given IV; long-acting analogs (glargine, detemir) are never mixed with anything.

Indications

type 1 diabetes

insulin-dependent

type 2 diabetes not controlled on oral agents

diabetic ketoacidosis

IV regular insulin

hyperglycemia per sliding-scale order

gestational diabetes

Before the Procedure

verify the order and insulin type

rapid/regular = clear; NPH = cloudy

check blood glucose

against the sliding-scale order before dosing

confirm the meal tray is present Hallmark

for rapid-acting insulin — lispro onset ~15 min; patient must eat within 15 minutes

inspect insulin for clumping or discoloration

roll NPH between the palms to resuspend

never shake — shaking denatures protein and adds air

bring refrigerated insulin to room temperature

reduces pain and stabilizes absorption

select and rotate the site within one region

abdomen absorbs fastest; avoid lumpy/thickened skin

Technique

Mixing NPH + regular — clear before cloudy

Air into NPH (cloudy) vialamount = NPH dose; needle stays above the fluid
Air into regular (clear) vialamount = regular dose
Withdraw REGULAR (clear) firstprotects the clear vial from NPH contamination
Withdraw NPH (cloudy) secondboth now in one syringe
Inject subcut at 90°, no massage45° if thin; never massage the site

During — Monitoring

do not aspirate before subcutaneous injection

no longer recommended for subcut insulin

hold pen needle in skin 10 seconds

ensures full dose delivery

do not massage the site after injecting

give only regular insulin IV

all other formulations are subcutaneous only

never mix glargine or detemir with any insulin

long-acting analogs go in a separate syringe

watch the peak window for hypoglycemia

time monitoring to the insulin's onset/peak

After — Complications

hypoglycemia Hallmark

shaky, diaphoretic, confused; treat per Rule of 15

lipohypertrophy

from repeated same-spot injection — causes erratic absorption

erratic absorption from heat-degraded insulin

e.g., insulin stored in a hot car

unpredictable absorption from region switching

each region absorbs at a different rate

ruined regular vial

drawing cloudy before clear contaminates the regular insulin

incomplete pen dose

needle withdrawn before the 10-second hold

Patient Teaching

rotate spots within the same region

e.g., across the abdomen; avoid lumpy areas

clear before cloudy when mixing

roll NPH, do not shake it

do not massage after injecting

store opened vials at room temperature

up to 28 days; do not leave insulin in a hot car

eat within 15 minutes of rapid-acting insulin

carry a fast-acting sugar for lows

e.g., 4 oz juice = ~15 g carbohydrate

recognize early hypoglycemia signs

shaky, sweaty, hungry — treat right away

Report Nowescalate immediately

shaky and diaphoretic Hallmark

hypoglycemia — check finger-stick glucose now, treat with 15 g fast carb (Rule of 15)

sudden hunger

early hypoglycemia symptom

confusion or altered mental status

neuroglycopenia — severe hypoglycemia

unable to swallow safely with low glucose

give IV dextrose (D50) or glucagon — not oral carbohydrate

glucose stays low after treatmentrecheck in 15 min

repeat 15 g carb; escalate if still low

double insulin dose given in error

anticipate hypoglycemia through the peak; monitor and notify provider

glucose 385 mg/dL on a pump with active delivery

suspect pump/site failure — check ketones, 'if in doubt, inject' by syringe

positive ketones with hyperglycemia

DKA risk — notify provider immediately

Clinical Pearl

Clear before cloudy, roll don't shake, abdomen absorbs fastest. Rotate within one region, never massage, and hold the pen 10 seconds. Only regular insulin goes IV; glargine and detemir never share a syringe. And the classic trap — if you draw cloudy into the clear vial, that regular vial is ruined.

Insulin Administration Technique