Graph showing linear relationship between time from peak concentration of the drug & plasma clearance by time.

In a zero-order kinetics rate of elimination of a drug is constant regardless of Cp (i.e. constant amount of drug eliminated per unit time). Cp decreases linearly with time.

List of drugs following zero-order kinetics

 Peas & WHEATS ‘

  • Phenytoin, Phenylbutazone
  • Warfarin
  • Heparin
  • Ethanol
  • Aspirin & other salicylates
  • Theophylline, Tolbutamide
  • Salicylates

A Pea would look like a zero and denotes the order.

Pea also stands for ‘ Pee‘ ing out a constant amount as in zero order kinetics constant amount of the drug is eliminated per unit time. Rate of elimination is constant and does not depend on or vary with the drug intake or plasma concentration of the drug.

Cite this article as:
Burhan Ahmed, MD, "Zero-order Kinetics," in Medicalopedia, September 6, 2012, [Permalink:].