See Insulin production and effects for more physiological information, this is more clinical and pharmacological information.
Subcutaneous methods
We have now developed many different types of insulin with different onsets. There are rapid, short, intermediate, and long acting (in onset and duration) forms with each having a role
- rapid acting - aspart, lispro
- short acting - regular insulin
- intermediate acting - isophane
- long acting - glargine, detemir
Generally the idea is that you take a long acting at the start of the day like glargine for just getting glucose into cells throughout the day and then a short acting bolus after meals for the use of getting mealtime glucose in.
Insulin analogues
Delaying onset
We delay the onset of insulin with subcutaneous injection through altering the protein structure so the insulin forms large bulky associations with other insulin molecules. At the depot site (where it is injected into the subcutaneous fat) long acting forms will form large hexamers, where it will then slowly dissociate, whereas short acting forms will not form any associations and instead quickly enter bloodstream
Basal bolus regimen
This is where, as mentioned above, you inject glargine or detemir at the start of the day, then after meals you inject a short acting one after meals to mimic the ebb and flow of a non-diabetic. YOu can adjust the bolus and basal rate dependant of circumstances and person.
Sites of injection
you can inject in the lateral upper arm, around the umbilicus, lateral upper thigh and rear iliac regions it is important to rotate injection site and rate of absorption may differ from site to site.
ADRs of insulin.
The main adverse effects of insulin are mainly related to hypoglycaemia, which can occur with insulin overdose, missed meals or other drug complications.
Other factors include
- weight gain
- oedema
- lipoatrophy, or lipohypertrophy
- transiant deterioriation in retinopathy, microvascular injury or atherosclerosis
- or local cutaneous allergy or even igG mediated insulin resistance (seen more with premix)