Treatment of Diabetes: Insulins Flashcards Preview

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Flashcards in Treatment of Diabetes: Insulins Deck (17):
1

Normal basal pattern of insulin secretion

  • Basal secretion of insulin occurs without exogenous stimuli to maintain a certain concentration of insulin at all times, even while fasting.
  • Stimulated insulin secretion occurs in response to exogenous stimuli.
  • A plasma glucose of greater than 100 mg/dL is the most potent stimulus for insulin release.

2

Characteristics of stimulated insulin release

  • Initial release of insulin in response to ingestion of food is termed “first-phase insulin secretion”.
    • This occurs approximately 8-10 minutes after food is ingested

  • If glucose concentrations remain high, insulin release drops off but begins to rise again to a steady level termed “second-phase insulin secretion”.
  • peripheral insulin concentration increases and peaks 30-45 minutes after starting a meal

 

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3

Glucose response to physiologic insulin secretion

  • The postprandial glucose concentration falls rapidly in response to insulin, reaching baseline levels 90-120 minutes after eating.
  • Physiologic insulin secretion consists of a constant basal level of insulin secretion and prandial secretion associated with ingestion of food.

 

4

Major classes of insulins

  • basal
  • pranidal
  • biphasic (mixed)

5

General characteristics of basal insulins

  • Long acting insulin analogues: given once daily for basal coverage
  • Intermediate acting NPH (neutral protamine Hagedorn): twice daily injections, treats mid day hyperglycemia associated with lunch, acts as basal insulin

6

General characteristics of prandial insulins

  • Rapid acting insulin analogue: injected just before a meal to prevent hyperglycemia, also used in insulin pumps and IV infusions
  • Short acting human insulin: administered before meals to prevent hyperglycemia.  
    • Can be sub-q or IV if DKA, hyperosmotic hyperglycemic state, or other inpatient cases

7

General characteristics of biphasic (mixed) insulins

Human and analogues: attain short term coverage for meals and longer basal effects.

8

Basal insulins: pharmacokinetics (onset, peak, duration of action)

  • NPH
    • onset = 2 - 4 hr
    • peak = 6 - 7 hr
    • duration =10 - 20 hr
  • Detemir
    • onset = 1 hr
    • duration = 10 - 20 hr
  • Glargine
    • onset = 1.5 hr
    • duration = ~24 hr

9

Prandial insulins: pharmacokinetics (onset, peak, duration of action)

  • Humalog, Novolog, Apidra
    • onset = 5 - 15 min
    • peak =1 - 1.5 hr
    • duration = 3 - 5 hr
  • Regular (U100)
    • onset = 30 - 60 min
    • peak = 2 hr
    • duration = 6 - 8 hr

10

Biphasic insulins: pharmacokinetics (onset, peak, duration of action)

  • Humalog 75/25
    • onset = 5 - 15 min
    • peak = 30 - 90 min
    • duration = 15 - 18 hr
  • Humalog 50/50
    • onset = 5 - 15 min
    • peak = 30 - 90 min
    • duration = 15 - 18 hr
  • Novolog
    • onset = 10 - 20 min
    • peak = 1.5 - 3 hr
    • duration = 10 - 20 hr

11

Standard of care for T1D glycemic management

  • intensive multiple-dose insulin therapy, which provides more physiologic replacement of insulin
  • This also called “basal-bolus” therapy, and allows patients more flexibility in the timing, size and composition of meals.

 

12

T1D tx example: gliargine + rapid-acting insulin

  • Glargine injected once daily (at bedtime or before breakfast) provides basal coverage for ~24 hours.
  • “Meal boluses” consisting of set doses of rapid-acting insulin or doses calculated using carbohydrate content of the meal are administered just before each meal.
  • Additional insulin is often added to correct high pre-meal blood glucose values using a “correction factor” or “sensitivity factor”.

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13

T1D tx example: Glargine + NPH + rapid-acting

  • this regimen uses the NPH peak to cover lunch, and eliminates the need for a lunchtime injection which can be troublesome for patients at school or work.
  • Detemir or Glargine then provides basal coverage overnight and into the next day.

 

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14

T1D tx examples

  1. morning/evening glargine (24-hr basal coverage) + pre-meal rapid acting insulin analog (post-prandial coverage)
  2. morning NPH (peak cover post-prandial lunch) + evening glargine (overnight/next day basal coverage) + pre-breakfast/dinner rapid acting insulin analog (post-prandial coverage)

15

Clinical scenarious prompting use of insulin therapy in T2D

  1. Pt.s experiencing marked weight loss with fasting blood glucoses >250 mg/dL, random glucoses of >300 mg/dL, and/or hemoglobin A1c of >10%
    1. signs of severe insulin deficiency
  2. Pt.s w/ hospital admission for hyperglycemic hyperosmolar state or diabetic ketoacidosis.
    1. Pt.s placed on intravenous insulin infusions, and discharged on subcutaneous insulin regimens

16

General characteristics of inpatient management of DM

  • Inpatient hyperglycemia is associated with significant adverse outcomes
  • insulin is preferred agent for control of inpatient hyperglycemia

17

Goals/management of inpatient glucose in critically ill vs. noncritically ill patients

  • Critically ill
    • goals: BG between 140-180 mg/dL
    • tx: start IV insulin @ BG > 180 mg/dL
  • Noncritically ill
    • goals: random BG < 180 mg/dL; premeal BG < 140 mg/DL
    • tx: scheduled subcutaneous insulin
      • insulin analogs preferred