NPH/Isophane by Novo Nordisk
intermediate-acting r-DNA/GE/GM
U100 Isophane
Line Novo
Also known as Novolin N, ReliOn/Novolin NPH, Protaphane
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 30 months
When opened 6 weeks room temp.
In pen 6 weeks room temp.
  • roll
  • protect from light
  • Do Not Freeze
  • Do not use if product does not re-suspend
  • Do not use intravenously
  • Do not refrigerate in use cartridges/pens.

Novo Nordisk's European name for its NPH/isophane insulin[4][5].

Technical detailsEdit

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

It is a neutral suspension of isophane insulin crystals[6].

Those in North America know it as Novolin N while some elsewhere call it Protaphane[7].

It is an intermediate-acting insulin with more than one company producing this type. Eli Lilly calls theirs Humulin N[8] [9] and Humulin I[10][11][12], while Aventis has its Insuman Basal[13][14].

Further ReadingEdit



  1. Insulins-North American Veterinary Conference-2005
  2. Selecting an Insulin for Treatment of Diabetes Mellitus in Dogs & Cats-Nelson-OSU Endocrinology Symposium 2006-Page 41
  3. Insulins-North American Veterinary Conference
  4. Electronic Medicines Compendium (EMC) UK-Patient Information Leaflet-Insulatard
  5. Prescribing Novo Insulins
  6. EMEA Scientific Discussion-Insulatard
  7. EMEA Scientific Discussion-Protaphane
  8. US FDA-Humulin N
  9. Humulin N NPH/Isophane Human Insulin
  10. Humulin I Prescribing Information
  11. Electronic Medicines Compendium (EMC) UK-Patient Information Leaflet-Humulin I
  12. Lilly EU/UK Product Sheet & Time Activity Profiles
  13. Electronic Medicines Compendium (EMC) UK-Patient Information Leaflet-Insuman Basal
  14. Insuman Prescribing Information
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