Flashcards in Insulin Therapy Deck (15)
What's the final structure of insulin in secretory vesicles?
Hexamers with zinc.
Review: 3 ways to stimulate insulin?
Glucose in blood.
Autonomic nerves - seeing, smelling food.
Hormonal - incretins from gut.
How is endogenous insulin metabolized? How does this compare with exogenous insulin?
Endogenous: much goes in portal vein to liver -> 60% hepatic, 40% renal.
Exogenous: Mostly renal.
What's the typical concentration of injected insulin? Why would you want something more potent?
Typical concentration = 100 units / ml (U-100).
U-500 R is used when people are very insulin resistant.
What are the 3 "speeds" of insulin preparations? Examples of each?
Rapid-acting: human analogues (Aspart, Lispro)
Short-acting: crystalline zinc (regular human insulin)
Long-acting: glargine, NPH + protamine
What chemical properties make rapid-acting insulin different from short-acting insulin?
What's the difference in speed of onset?
Rapid-acting has changes that disrupt monomer-monomer interactions - so more insulin is in the active form right away.
Rapid: 5-15 min.
Short-acting: 30-60 min.
Do non-diabetic persons only produce insulin after meals?
Nope, there's a basal insulin secretion throughout the day. - which long-acting insulins try to mimic.
What is NPH? Duration of action?
Neutral protamine hagedorn: crystalline insulin with zinc + a positively charged peptide, protamine.
Has activity for 10-20 hours.
(Insert joke about How I Met Your Mother)
Why is glargine long-acting?
With its acidic pH, it precipitates, and takes a long time to be absorbed after being given SubQ.
Why is detemir long acting?
It's acylated with myristic acid... so it binds albumin. Slow release keeps insulin at a basal level for a long time (up to 24hrs).
Which insulins have no "peak"?
Glargine and detemir, which is desirable.
When do you use IV insulin?
Emergencies in the hospital - e.g. DKA.
What are 3 common insulin regimens? Which ones are more preferred?
NPH + Lispro (rapid-acting) fixed doses at breakfast and dinner. (not preferred, but simpler)
Lispro pump providing basal infusion and meal-time boluses (preferred).
"Basal-bolus" -once daily glargine + carb-calculated Lispro at mealtimes (preferred).
5 factors affecting the appropriate insulin dose to give?
Physical activity (must give less insulin when exercise)