Insulin Treatment Flashcards
What are the actions of low levels of insulin (basal insulin) in the fasting state?
1) Allow controlled production of glucose (and ketones) by the liver
2) Stop blood glucose rising day to day
3) Minimal uptake of glucose into muscle/fat
What are the actions of high levels of insulin after eating?
1) Completely suppress glucose and ketone production by liver
2) Promote glucose uptake into muscle and fat from liver in the form of glycogen
Why is basal insulin required?
- To balance whatever glucose the liver is making
- Cells need insulin to take up glucose
How quickly does the rise in glucose occur after a meal?
Within 10 minutes
How does insulin reach the liver?
It goes from the pancreas through the hepatic portal system to the liver
How is exogenous insulin different from endogenous insulin?
1) Injectable
2) Loss of portal:peripheral gradient - injected into systemic system not portal system
3) Loss of C-peptide
4) Not controlled endogenously so can’t adjust dose once injected and narrow therapeutic index
5) Weight gain (more effect in s/c tissue, stop losing calories in urine)
6) Allergies
What does the narrow therapeutic index of insulin mean?
- The chance of getting the s/c dose completely correct are low
- Main risk = too much insulin
Why does physiological weight gain occur from controlling diabetes?
- In uncontrolled diabetes, lose 500-600 kcal/day in urine in the form of glucose
- So if start insulin and don’t change diet or exercise then you bring your weight back to what you would have been without diabetes
What are the rapid-acting insulins (prandial)?
1) Monomeric (Novorapid, Humalog)
2) Regular
Describe how monomeric insulin acts
- Starts having its effect at 15-20 minutes
- Peak at 60-70 minutes
- Lasts 2-3 hours
When do you take monomeric insulin?
20 minutes before meal
Describe how regular insulin acts?
- Starts having effect at 30 minutes
- Peak at 2-3 hours
- Lasts 4-6 hours
When do you take regular insulin?
30 minutes before meal
What are the long-acting insulins (basal)?
1) Intermediate (NPH)
2) Peakless e.g. detemir (attached to fatty acid), glargine (attached to acid, stings a bit)
Describe intermediate insulin
- Starts having effect at 3-4 hours
- Peak at 5-6 hours
- Lasts for 10-12 hours
When is intermediate insulin used and what is the problem with it?
- Used at night time
- Problem with night time hypoglycaemia
Describe mixed (biphasic) insulin
- A mixture of rapid and long-acting insulin (intermediate/peakless)in a stated proportion
- Two injections a day for 24h cover
What does the molecular size of the insulin correlate with?
The rate of absorption from s/c injection sites
Describe how the rate at which insulin acts can be changed?
- Insulin normally acts as a hexamer with a zinc molecule, but to act it needs to break down into monomers
- Can alter the rate at which the hexamer breaks down into monomers to change how fast it acts
- Can do this by injecting monomers or binding the hexamers together or to other agents
What is the onset and duration of peakless insulin?
Onset = 90 minutes Duration = 14-24h
When are rapid-acting insulins taken?
Around meal times
When are long-acting insulins taken?
- To control overnight or between meals
- Don’t need to be eating
What is the normal concentration of insulin?
U100 (100 units per 100ml) - highest = U500
How is insulin administered?
With a pre-filled pen device - dose on pen is dose you use, units the same, only change volume not concentration
How is insulin treatment given for people with T1D who produce no (or v little) insulin?
- Insulin is essential for people with T1D
- Need to mimic physiological insulin production as closely as possible to get in-range glucose levels
Why is insulin dose adjustment important?
- Insulin has a narrow therapeutic index
- Too much insulin results in hypoglycaemia
- Not enough insulin results in hyperglycaemia
What are the two types of insulin treatment for people with T1D?
1) Basal bolus regimen - prandial insulin at meal times and basal insulin twice daily (or once if glargine)
2) Basal bolus regimen dose adjustment - need to test CBG pre-meals and pre-bed
How do you work out the required dose of basal insulin
- Work out insulin requirement
- Test glucose in the morning, if normal take insulin dose and test blood glucose over next 4-6 hours until lunch
- If glucose is stable then dose is good
- If glucose goes up when not eating, need to increase dose of basal insulin
When do you test CBG in dose adjustment basal bolus regimen?
- Before meals (any time eat carbohydrates)
- If glucose is too high, can adjust dose of prandial insulin to cover food and increase in glucose when fasting
What can affect how much basal insulin you need?
1) Exercise - if done lots of exercise, got rid of glucose and glycogen not via insulin, so need less insulin during second basal dose at end of day
2) Alcohol - reduces glycogenolysis so need less overnight insulin otherwise risk of hypoglycaemia
What are the golden rules of insulin dose adjustment in T1D?
- Aim is to adjust the insulin doses to achieve the target BG
- Test pre-meals and pre-bed
- Know BG targets
- Looks for hypos and sort that out first
- Look for a pattern (except single overnight hypo)
- Identify biggest problem and which insulins are acting then
How do you adjust the insulin dose in T1D?
- Adjust by 10-20% at a time
- Usually make one change only (but think of knock on effects)
What should you do before increasing pre-bed long acting insulin?
Check 3am BG first
Which insulin dose would you change (there is a problem with it) if CBG is high/low pre-breakfast?
Pre-bed long acting insulin
Which insulin dose would you change if CBG is high/low pre-lunch?
- Pre-breakfast rapid-acting
- OR morning long-acting
Which insulin dose would you change if CBG is high/low pre-dinner?
- Pre-lunch rapid-acting
- OR morning long-acting
Which insulin dose would you change if CBG is high/low pre-bed?
Pre-dinner rapid-acting
Describe DAFNE
- Dose adjustment for normal eating
- Teaching how to adjust amount of insulin you take to how much carbohydrate you eat (unrestricted diet)
- 5 day programme
- Adult education principles to facilitate new learning in a group setting
- Curriculum driven and quality controlled
- Emphasis on building confidence and appropriate independence
- Participants taught how to adjust insulin to lifestyle rather than lifestyle to insulin - better results and control of diabetes
How does insulin pump therapy work?
- Continuous s/c rapid-acting insulin
- Small machines filled with units of rapid acting insulin
- Instead of taking long acting insulin and hoping that it releases e.g. one unit per hour, can set the pump to release a set amount per hour to keep basal insulin content
- Can programme the pump to provide a set basal level and change it e.g. reduce if going on run
- When you eat, press a button on pump to give a shot of rapid acting insulin
What do you still need to do even with insulin pump therapy?
- Still need to measure blood glucose and carb intake
- Pump is just a delivery method (pressing button instead of injecting)
- Person still makes a decision of how much to deliver
Describe insulin treatment in T2D
- People with T2D usually continue to produce insulin, but not enough to maintain normal glucose levels so insulin can be used in the treatment of T2D
- There is less requirement to closely mimic physiological insulin production bc there is still some endogenous insulin
Why does insulin requirement in T2D increase year on year?
Bc it is a progressive disease as beta cell function declines
Describe use of basal insulin in T2D e.g. glargine once a day
- Usually continue other medications as well
- Test BG pre-breakfast
- If give too much/little insulin, body can still increase/decrease the endogenous level, need to be less precise than with T1D
- Adjust nighttime dose every night until the morning CBG is within the target fasting glucose range (resting beta cell overnight, bringing glucose down to normal levels, so beta cells can better control post-meal glucose in the day)
- Risk of nighttime hypos v low
What are the golden rules of insulin dose adjustment in T2D?
- Aim is to adjust the insulin doses to achieve target BG
- Test pre-breakfast to reach target
- Looks for hypos and sort that out first
- Look for a pattern (except single overnight hypo)
Is there a more narrow range of variation of CBG in T2D or T1D?
T2D
How do you adjust the once a day insulin dose in T2D?
- Adjust by 10-20% at a time
- Think of knock on effects (long acting insulin lasts 12-24h)
- If increased pre-bed long-acting insulin, consider checking 3am BG first
Describe treating T2D with mixed insulin pre-breakfast and pre-dinner
- First one covers breakfast and lunch
- If delayed lunch or no lunch can cause hypo
- If big lunch can’t adjust
- But only two injections a day vs 4-6 basal bolus
- If late dinner, might have peak later in night and hypo overnight
- Good for people with regular lifestyle e.g. older or in nursing home
What insulin regimen would you give to someone who has got their fasting glucose down to normal with one overnight insulin but still has HbA1c?
Twice daily mixed insulin (30% prandial, 70% basal/NPH) bc not covering meals enough so need some type of meal time insulin (or full basal bolus insulin like in T1D)
What are the golden rules of twice mixed daily insulin dose adjustment in T2D?
- Aim is to adjust the insulin doses to achieve target BG
- Test pre-breakfast and pre-bed
- Looks for hypos and sort that out first
- Look for a pattern (except single overnight hypo)
- Identify biggest problem and which insulins are acting then
How do you adjust the twice daily mixed insulin dose in T2D?
- Adjust by 1-20%
- Usually make one change only
- Thick of knock on changes - the fixed proportion of mixed insulin preparations contain rapid and long acting insulin so if you change the dose, both rapid and long acting are affected
- If increasing the pre-evening meal dose consider checking 3am BG first
Which mixed insulin dose would you adjust if the pre-bed/pre-breakfast BG was above/below target?
Pre-dinner mixed insulin
Which mixed insulin dose would you adjust if the pre-lunch/pre-dinner BG was above/below target?
Pre-breakfast mixed insulin
What are the types of insulin therapy in T1D?
1) Basal bolus
2) Insulin pumps
3) Twice daily - free mixing, premix
What are the types of insulin therapy in T2D?
- With or without other agents
1) One daily long acting insulin
2) Twice daily mixed
3) Basal bolus
