Insulin comes in a variety of types: rapid, short, intermediate or longacting;
single or biphasic mixtures; and animal, human or analogue forms.
Most insulin today is recombinant human insulin, which was fi rst marketed
in the early 1980s. There are no signifi cant differences between the actions
or adverse effects of animal and recombinant insulin, despite a belief that
more allergies develop in response to bovine or porcine-sourced drug.
Insulin is sensitive to heat and oxygen: vials must be discarded after 28
days as the contents lose effectiveness.