Insulin Flashcards
Insulin is a __________ hormone secreted by pancreatic beta-cells
Polypeptide
Insulin increases glucose uptake by _________ tissue and ________, and suppresses _________ glucose release
Adipose
Muscles
Hepatic
The role of insulin is to lower ________ concentrations in order to prevent _________ and its associated ___________, __________ and ________ complications
blood-glucose
hyperglycaemia
microvascular
macrovascular
metabolic
The natural profile of insulin secretion in the body consists of _______ insulin (a low and steady secretion of background insulin that controls the glucose continuously released from the liver) and meal-time _______ insulin (secreted in response to glucose absorbed from food and drink)
basal
bolus
What are the three types of insulin available in the UK?
- Human insulin (produced by recombinant DNA technology)
- Human insulin analogues (same production as human insulin but modified to extend duration of action or increase rate of absorption and onset of action)
- Animal insulin (bovine or porcine); no longer initiated in people with DM but may still be used by some people who cannot or do not wish to change to human insulins
Is human insulin derived from human donors?
No; produced by recombinant DNA technology
How do human insulin analogues compare to human insulin?
Same mode of production but analogues are modiefied to produce desired kinetic characteristics such as an extended duration of action or faster absorption and onset of action
Is insulin allergy common?
No, true insulin allergy is rare; Human insulin and insulin analogues are less immunogenic than animal insulins
Why isn’t insulin administered orally?
Inactivated by GI enzymes; S/C route is ideal in most circumstances
What are the ideal insulin injection sites? (4)
Insulin should be injected into a body area with plenty of subcutaneous fat—usually the:
- abdomen (fastest absorption rate)
- outer thighs (slow absorption)
- buttocks (slow absorption)
- Inner thighs (also fast)
How does rate of absorption of insulin via S/C injection compare between the abdomen/inner thigh and the outer thighs/buttocks?
Slower absorption at outer thighs/buttocks vs fastest absorption at abdomen or inner thighs
What is the main disadvantage of administering insulin to the limbs?
Absorption can vary considerably (as much as 20-40%), particularly in children
What factors influence insulin absorption from limb sites? (6)
- Local tissue reactions
- Changes in insulin sensitivity
- Injection site
- Blood flow (eg increased due to exercise may increase absorption)
- Depth of injection
- Amount of insulin injected
____________ can occur due to repeatedly injecting into the same small area, and can cause erratic absorption of insulin, and contribute to poor glycaemic control.
Lipohypertrophy; Patients should be advised not to use affected areas for further injection until the skin has recovered
Lipohypertrophy can be minimised by __________
using different injection sites in rotation
Injection sites should be checked for signs of, __________, _________, ________, and __________ before administration
infection
swelling
bruising
lipohypertrophy
What are the metabolic consequences of lipohypertrophy?
can cause erratic absorption of insulin, and contribute to poor glycaemic control
What are the categories of insulin based on their time-actions? (3)
- Short-acting (including soluble insulin and rapid-acting)
- Intermediate-acting
- Long-acting
**the duration of action of each varies considerably from one patient to another and needs to be assessed individually
What are the available preparations of short-acting insulin?
- Soluble insulin (human and bovine or porcine although animal insulins rarely used)
- Rapid-acting insulin analogues
- insulin aspart
- insulin glulisine
- insulin lispro
What are the three types of rapid-acting insulin?
- Insulin aspart
- Insuline glulisine
- Insulin lispro
Soluble insulin is usually given subcutaneously but some preparations can be given _________ and __________
intravenously
intramuscularly
For maintenance regimens, soluble insulin is usually to injected____-____ minutes before meals
15 to 30
Remember, soluble insulin is short-acting
When injected subcutaneously, soluble insulin has a ________ onset of action (__________), a peak action between __________, and a duration of action of up to __________.
rapid
30 to 60 minutes
1 and 4 hours
9 hours
When injected intravenously, soluble insulin has a ______ half-life of _________ and its onset of action is __________.
short
only a few minutes
instantaneous
Soluble insulin administered ___________ is the most appropriate form of insulin for use in diabetic emergencies e.g. diabetic ketoacidosis and peri-operatively
intravenously
______________ administered intravenously is the most appropriate form of insulin for use in diabetic emergencies e.g. diabetic ketoacidosis and peri-operatively
Soluble insulin
Insulin aspart, insulin glulisine, and insulin lispro have a faster onset of action (within _________) and shorter duration of action (approximately ___________) than soluble insulin, and are usually given by subcutaneous injection
15 minutes
2–5 hours
For maintenance regimens, these insulins should ideally be injected ________ before meals
immediately
Rapid-acting insulin, administered before meals, has an advantage over short-acting soluble insulin in terms of ____________, __________, and _____________, including ____________
improved glucose control
reduction of HbA1c
reduction in the incidence of severe hypoglycaemia
nocturnal hypoglycaemia
Why should the routine use of post-meal injections of rapid-acting insulin be avoided? (3)
when given during or after meals, they are associated with:
- poorer glucose control,
- an increased risk of high postprandial-glucose concentration, and
- subsequent hypoglycaemia
Which insulin is considered “intermediate-acting?”
Isophane insulin
Isophane insulin has an _________ duration of action, designed to mimic the effect of endogenous _______ insulin
intermediate
basal
When given by subcutaneous injection, intermediate-acting insulins have an onset of action of approximately _________, a maximal effect at _________, and a duration of action of ________.
1–2 hours
3–12 hours
11–24 hours
Isophane insulin is a suspension of insulin with _________; it may be given as one or more daily injections alongside separate meal-time __________ injections, or mixed with a ________ insulin in the same syringe
protamine
short-acting insulin
short-acting (soluble or rapid-acting)