Wk4 Flashcards
what is insulin
• Considered the body’s main fuel storage hormone.
• Secreted by pancreatic beta cells in response to raised levels of glucose in the blood.
Overall function:
1)Ensure tissues have adequate chemical substrates for energy
2)Storage
3)Anabolism and repair
• It is synthesised in the beta cells from a larger protein known as proinsulin (the storage form of the hormone)
normal insulin glucose metabolism
- Insulin binds to insulin receptor on cell surface
- Generation of intracellular signal
- Glucose transporter moves from inactive site to cell wall
- Glucose transported across cell wall.
release and circulation of insulin
• Insulin released via capillaries into portal circulation to the liver
• Pulses every 30 -60 minutes, increased release with extra stimuli
– most important of which is raised blood glucose.
• Initial release of insulin happens within 30 – 60 seconds.
Slower release over the next 60 – 90 minutes
• Insulin facilitates removal of glucose from the blood and promotes storage of metabolic fuels
• It affects uptake, utilization and storage of carbohydrates, fats and proteins in the liver, adipose and muscle cells, so that nutrients are stored as:
– Glycogen, triglycerides, fatty acids and proteins.
ultra-rapid acting insulin and example
analog of human insulin, 5-15min onset, last 3-6hrs
Lispro(Humalog) immediately B4 eating, Aspart (Novolog) eat straight after
short duration/slow acting insulin and example
unmodified crystalline insulin, 30-60min onset, 7hr duration, clear soln. given as SC
actrapid
intermediate insulin and example
humulin neutral protamine Hagedorn, 60-180min onset, 16-24hr duration, prepared by conjugating regular insulin with a Lg protein = decreases solubility of NPH insulin = slows absorption
Lente insulin – regular insulin with zinc = reduces solubility, no proteins added therefore less allergic than above, 60-180min onset, 16-24hr duration
humulin N, Novolin N, insuvet Lente
long duration insulin and example
reduced solubility 240-360min onset, 24-28hr duration or glargine (modified human insulin with 70 min onset 24hr duration, one day SC injection at bedtime
Ultralente (humulin U), glarigine (Lantus)
premixed biphasic insulin
both short and intermediate forms
30/70 – 2-12hrs peak – 24hr duration
20/80 – 2-8hrs peak – 24hr duration
50/50 – 4-8hrs peak – 24hr duration
nursing considerations of insulin
Insulin release inhibited by somatostatin and adrenaline
Deficiencies of release occur in pancreatic disorder: DM, pancreatitis, cushings, acromegaly
what is the treatment of diabetes
replace insulin to physiological levels; to obtain metabolic control with insulin, oral hypoglycaemic drugs, or exercise and dietary regimens.
Typical dose = 0.7 IU/kg per day
Normal pancreatic production = 50 IU per day
fixed dose insulin therapy
The amount of insulin taken at each meal does not vary
You can be on any injection regimens and on a fixed dose therapy
• Can help to simplify the understanding of blood glucose
• Does not offer the flexibility
flexible insulin therapy
Choose how much insulin to inject at each meal. Flexible insulin therapy is particularly common for basal-bolus insulin regimen
basal bolus regimen
dose of short-acting insulin is given before each meal plus some intermediate or long-acting insulin at bedtime. Mimics bodies natural release rhythms
split mixed regimen
The total daily dose in units is estimated. This is split between 1⁄3 short-acting and 2⁄3 intermediate or long-acting insulins, 2⁄3 of the total mixture given before breakfast and the other 1⁄3 before the evening meal
once daily regimen
Involves taking a single dose of insulin each day
• The regimen is suitable for people with type 2 diabetes who are unable to produce enough of their own insulin to control their diabetes
• People on this regimen will need to take tablets in addition to the insulin
• A once daily regimen can either involve taking a long acting peakless insulin or an intermediate NPH insulin
• A long acting peakless insulin for people with hyperglycemia through the day and night
• An intermediate insulin dose is suitable for people who experience high blood glucose overnight and in the morning but better during the day.
• In this case, the insulin dose will be taken before bed.
Insulin pump therapy/continuous SC insulin infusion
Involves an insulin pump connected to patient
Delivers a constant feed of insulin into the body via a subcut cannula
At meal times, an increased burst (bolus) of insulin can be delivered
Generally given to type 1 diabetes pt
pen injectors
disposable insulin filled catridges
Portable insulin pumps
computerized delivery basee rate (1 U/hr) + bolus at meals
• Continuous subcutaneous infusion of insulin delivers short- or ultra-short acting insulin
sliding scale insulin
additional insulin may be required Sliding scale allows dose of insulin to be titrated to BSL Normally regular human insulin used Acute illness = iv sliding scale Actrapid
thing that increase level of blood glucose
- B2 agonists
- Glucocorticoids
- Oral contraceptives
- Growth hormone
- Thiazide diuretics
- Thyroid hormones
Things that decrease level of blood glucose
- Alcohol
- ACE inhibitors
- Anabolic steroids
- MAO inhibitors
- High-dose NSAIDs
- Antimalarial agents
nursing considerations of insulin
Hypoglycaemia – OD of insulin or mismatch in blood sugar level with approp dose of insulin (missing meal, ↑ exercise)
Lipodystrophy- associated with contaminates of insulin, localised at site (depression or lump) avoided by rotation of sites & massage site
Allergic reaction – often due to contaminates, trying to using human insulin and ↑ purity of animal forms.
Insulin resistance – insulin antibodies forming in the blood mainly due to contaminates
• Cannot be oral as peptide hormone insulin destroyed by gut enzymes
• Fastest rate of absorption is via abdomen
– Sites: thighs, upper arm, buttocks, abdo
• Doses depend on age, weight, lifestyle
• Do not vigorously shake bottle => frothing
• Education
• Monitor skin and nails and extremities
what are biguanides
Decreases the production of glucose in the liver and also enhances glucose uptake and utilization by muscle
• Not prone to Hypo’s
e.g. Metformin (Gluophage, Diaformin, Diabex)
what are sulonylureas
- Derivatives from sulphonamide antibiotics w/o antibacterial properties
- Work all day long to promote insulin release from pancreas
e.g Glipizide, Orinase, Glyburide, Gliclazide)
what are Thiazolidinedione – “Glitazones”
- Reduces glucose levels by ↓ insulin resistance
- Also ↑ body’s response or sensitivity to insulin
- Insulin must be present for drug to work
- Benefits take several weeks to develop
e.g. Rosiglitazone (Avandia), Trolitazone (Rezulin)
Acrabose
- Alpha-glucosidase inhibitors – getting more common
- Blocks the enzyme that digest starches you eat
- Resulting in delay in absorption of carbohydrates
- Blood sugar raised less and more slowly during the day
- Taken 3 times a day with a meal
what are incretin enhancers
Incretins are peptides that are released from the digestive tract in response to food
• stimulate glucose-dependent insulin release
• enhance β-cell proliferation
• reduce post-prandial glucose levels especially
• delay gastric emptying
• reduce appetite
what are glucocorticoids
- Used for wide range of conditions for their anti-inflammatory and immunosuppressant effects
- class of steroid hormones that bind to the glucocorticoid receptor
- Produced in adrenal cortex
- Decrease inflammatory mediators & increase anti-inflammatory products
- Increase release of glucose from liver & prevent uptake by cells
- Promote breakdown of fats
different types of glucocorticoids
• Short acting
– Hydrocortisone
– Anaphylaxis
• Intermediate acting
– Prednisolone
– Asthma, Arthritis, Dermatitis
• Long acting
– Dexamethsone
– Asthma,Croup, COPD etc
what is epinephrine
In treatment of anaphylaxis:
•Severe, life-threatening, generalised or systemic hypersensitivity reaction
•Characterised by rapidly developing life-threatening airway and/or breathing and/or circulation problems usually associated with skin and mucosal changes
– improves airway patency, improves blood pressure, and may be life-saving
The recommended dose is 500 mcg (or 0.5 mL adrenaline injection 1 in 1000) given intramuscularly
what is levothyroxine
Thyroxine supplements are needed for patients with inadquate thyroxine
– Hypothyroidism & goitre
– Well absorbed from GI tract, long half life 6-7 days
– Given on empty stomach
what is antidiuretic hormone
In treatment of diabetes insipidus e.g. vasopressin
- ADH effects, increases tubular reaborption of H2O and also potent vasoconstrictors
- Desmopressin, short half life given intranasal, tablet, wafer, sc/im/iv
