Humulin I
NPH/Isophane by Eli Lilly
intermediate-acting r-DNA/GE/GM
U100 Isophane
Line Humulin
Also known as Humulin N
Similar to  
Action in cats  
  • onset 1-2h,
  • sharp peak 4-6h,
  • duration 8-12h[1][2]
Action in dogs  
  • onset 0.5-3h,
  • peak 2-10h[3],
  • duration 4-24h
Use and Handling
Type cloudy
Shelf Life 18 months
When opened 28 days room temp.
In pen 28 days room temp.

This is the Euro name for Lilly's isophane-suspension insulin[4]--the "I" an abbreviation for isophane[5][6].

Lilly makes the same insulin known as Humulin N[7] in North America[8].

Like all other isophane/protamine suspended insulins, it is a crystalline suspension with protamine.

Technical details[edit | edit source]

This type of insulin tends to have an onset of 2-4 hours, a peak action of 4-10 hours, and a total duration of 10-20 hours, in humans.

These times seem to be similar in dogs, but considerably compressed in cats, possibly because of cats' faster metabolism.

Cats seem instead to experience a 1-2 hour onset, a peak action of 4-6 hours, and a total duration of 8-12 hours maximum, according to user surveys on

Novo Nordisk also has their Novolin N, Protaphane and Insulatard[9][10][11][12] while Aventis has their Insuman Basal[13][14].

Further Reading[edit | edit source]


References[edit | edit source]

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