Canine Diabetes Wiki
R, Neutral by Novo Nordisk
U40, U100 none
Action in dogs:
  • onset 10-30 minutes,
  • peak 1-5h,
  • duration 4-10h [1]
Line: Novo
Also known as: Novolin R, ReliOn/Novolin R
Similar to: Huminsulin Normal, Humulin C
Humulin RHumuline R, Humulin Regular
Humulina Regular, Humuline Regular, Humulin S
Humulin ReliOn R, Umuline Rapide
Umuline Regular, Insuman Rapid, Winthrop Rapid

Names of Lilly r-DNA/GE/GM insulins worldwide
Use and Handling:
Shelf Life: 30 months Type: soluble, clear
When Opened: 6 weeks room temp.
In Pen: 6 weeks room temp.
Notes: Protect from light and heat
Do Not Freeze,
May be used intravenously

Actrapid in 10 ml vial and 3 ml pen cartridge.

Note that some countries have the brand name in U40 strength.

Novo Nordisk's brand of fast-acting insulin, [2][3][4][5][6] known as Novolin R in North America. [7]

Comparable insulins made by others are: Huminsulin Normal, Humulin R [8] and Humulin S [9][10][11] by Eli Lilly, and Insuman Rapid [12][13] and Winthrop Rapid, both by Aventis.

A short-acting, soluble, non-suspended insulin produced from r-DNA/GE/GM, bovine, or porcine sources. Like all R or neutral insulins, nothing is added (suspensions) to alter the insulin's action or speed. [14] From 1921 to the 1930's when PZI was developed, R was the only kind of insulin available.

While both R/neutral and semilente insulins are considered fast-acting, they differ in a few ways. As above, there's no suspension or buffer [15] in R/neutral; it's totally dissolved and soluble, meaning it can safely be used intravenously. [16]

The very small insulin particles in semilente insulin are suspended by zinc. [15] Semilente is cloudy, has an acetate buffer and cannot be used intravenously.

R/Neutral insulin cannot be reliably mixed with Lente or Ultralente insulins. [17][18] Semilente can; the ratio of 3 parts semilente insulin to 7 parts ultralente insulin produces Lente insulin. [15]

R/Neutral Insulins[]


  1. Insulins. North American Veterinary Conference Clinicians Brief (2006).
  2. Patient Information Leaflet-Actrapid. Novo Nordisk.
  3. Scientific Discussion-Actrapid. EMEA.
  4. Prescribing Novo Insulins.
  5. Actrapid Information. Novo Nordisk.
  6. Actrapid. Medguides UK.
  7. Novolin R. Revolution Health.
  8. Humulin R Regular Human Insulin. Revolution Health.
  9. Patient Information Leaflet-Humulin S. Eli Lilly.
  10. Humulin S Prescribing Information.
  11. Lilly EU/UK Product Sheet & Time Activity Profiles. Eli Lilly.
  12. Patient Information Leaflet-InsumanRapid. Sanofi-Aventis.
  13. Prescribing Insuman Insulins.
  14. Humulin R. Eli Lilly.
  15. 15.0 15.1 15.2 DeRuiter, Jack. Insulin Preparations-Regular Insulin. Auburn University. Cite error: Invalid <ref> tag; name "Auburn" defined multiple times with different content Cite error: Invalid <ref> tag; name "Auburn" defined multiple times with different content
  16. Maddison, Jill E.,Page, Stephen W.,Church, David B. (2008). Small Animal Clinical Pharmacology. Saunders Ltd..
  17. Intermediate-Acting Insulin Preparations: NPH (Isophane) & Lente. Diabetes Care (1980).
    Note--in 1980, there were no r-DNA/GE/GM insulins
  18. Resource Guide. American Diabetes Association (2005).

More Information[]

Related Pages
Rtap HumilinLILLY 21944f Rtap DSC02818
Humulin ReliOn R
Humulin R
Humulin S
Winthrop Rapid
Insuman Rapid