ABSTRACT
What classes of drugs are used to treat type 1 diabetes mellitus (DM)?
Insulin is the main class of drug used to treat type 1 DM.
Insulin treatment has been available since 1925, initially extracted from beef and pork pancreases. In the 1980s this was replaced by synthetic human insulin, which is now largely being replaced by genetically engineered human insulin analogues. Human and animal insulins, when injected subcutaneously, are more likely to clump, resulting in a slower onset of action and longer, more unpredictable duration of action when compared to insulin analogues. They are, therefore, more likely to cause hypoglycaemia between meals and at night, followed by fasting hyperglycaemia.
Insulins can be categorised according to onset of action, peak and duration of action.
The main groups are rapid-, short-, intermediate- and long-acting (see table below).
Biphasic insulins are ready mixed combinations of rapid- or short-acting insulins with intermediate-acting insulins.
Types of insulinsType of Insulin
Onset
Peak
Duration
Administration timing
Rapid-acting insulin analogues (aspart/Novorapid®, lyspro/Humalog®, glulisine/Apidra®)
<15 min
1–2 h
4–6 h
Shortly before, during or immediately after meals
Short-acting human insulin (regular soluble: Actrapid®/Humulin R®)
0.5–1 h
2–4 h
6–8 h
30 min before meals (also used for IV infusions)
Intermediate-acting human insulin (isophane/NPH/Humulin I®, Insulatard®)
1–2 h
6–10 h
12 h
Twice daily regimens (before morning and evening meals)
Long-acting insulin analogues (glargine/Lantus®, detemir/Levemir®)
1–1.5 h
Flat, maximal effect in 5 h
12–24 h (detemir) 24 h (glargine)
Once or twice daily (physiologically similar to endogenous basal insulin secretion)
