Lecture 25 - Insulin Therapy

what are general considerations for insulin

NAPRA schedule 2 medication

usual solution strength: 100 units/mL

main source is recombinant DNA (animal sources are available but more complications)

most common delivery: insulin pen (pumps becoming more prevalent)

what are the most common adverse reactions to insulin

hypoglycemia

weight gain

lipohypertrophy

what are the main types of insulin delivery devices

syringe and vial

pens

pump and resevoir

what are factors to consider when deciding what insulin to use 

age, general health, lifestyle/activity level, diet

treatment goals, motivation, ability to adhere to treatment

hypoglycemia awareness, ability to self-manage treatment

cost/coverage

• NPH/regular are cheapest

• analogues are expensive

pharmacodynamic profile 

what is important to consider when starting an insulin regimen for someone newly diagnosed with type 1 diabetes 

honeymoon period

usually transient, but can last up to 2 years

associated with low insulin requirements: <0.5 units/kg/day

what should you ask yourself when recommending an insulin dose

is it easy to remember

is it easy to prepare

what are the recommendations for total daily insulin dose

textbook: 0.4-1.0 units/kg/day

diabetes Canada: <0.5 units/kg/day during honeymoon phase

what are the recommended proportions for basal/bolus doses

textbook: 50% basal, 50% bolus

alternative for convenience: 40% basal, 60% bolus (20% before each meal)

what is the recommended initial insulin management for type 2 diabetes 

single daily injection of basal insulin 

• long-acting preferred over NPH

• degludec or glargine may be considered over other long-acting analogues to reduce the risk of nocturnal hypoglycemia

incretin and/or SGLT2 inhibitor should be continued or initiated when introducing basal insulin 

what are the recommendations if a bolus insulin is required for type 2 diabetes 

use a step-wise approach starting with 1 bolus dose per day at the largest meal

introduce additional mealtime injections later if needed

rapid acting analogues preferred over regular insulin

insulin secretagogues (solfonylureas/meglitinides) should be discontinued

what are the sites for insulin administration

abdomen - absorption is faster, but more consistent

lateral thigh - slower and variable absorption

upper arms - slower and variable absorption, challenging to reach

superior buttocks - slowest absorption 

what are counselling points for injection site rotation for the abdomen

divide the abdomen into 4 areas, inject into one area for a week then move clockwise

separate each injection within the area by 2-3cm (1-2 fingers)

why do this: minimize risk of lipohypertrophy, maintains consistent insulin absorption

do not rub the injection site after (affects absorption)

what is the general approach to insulin dose adjustment

1. look for lows (< 4mmol/L, symptoms of hypoglycemia)

2. start the day well

3. look for consistent highs (explanations? - exercise, skipped doses, extra meals)

4. change one insulin by 1-2 units

what is the clinical presentation of hypoglycemia

blood glucose <4 mmol/L

sweating, trembling, palpitations, anxiety

hunger, nausea, headache, tingling

disturbed sleep, weird dreams, weakness/dizziness, difficulty concentrating

vision changes, drowsiness, difficulty speaking, unconsciousness

how is a hypoglycemic episode managed 

check blood glucose and confirm a low

consume 15 grams of a simple carbohydrate (important to carry at all times)

re-check blood glucose in 15 minutes

• if still <4 repeat 15 grams of simple carbohydrates

• if >4 consume a snack that includes a protein to maintain level

what are other adverse effects of insulin

weight gain

lipohypertrophy - thickened area of tissue because fat accumulates at injection site

• insulin release from site is delayed and unpredictable

• minimize risk by rotating sites

lipoatrophy - loss of subcutaneous fat at injection site

• possibly immune-mediated inflammatory response

• rare