True about first order kinetics is:
Ans. d. The rate of elimination is proportional to the plasma concentration (Ref: Katzung 12/e p43-44: KDT 7/e p30-31, 6/e p31-32)Rate of elimination is proportional to plasma concentrationQ first order kinetics (Linear kinetics).First Order Kinetics (Linear kinetics)Zero Order Kinetics (Non linear Kinetics)* Constant fraction of drug is eliminated per unit of timeQ.* Rate of elimination is proportional to plasma concentrationQ.* Clearance remains constantQ.* Half-life remains constantQ.* Most of the drugs follow first order kineticsQ.* Constant amount of the drug is eliminated per unit timeQ.* Rate of elimination is independentQ of plasma concentration.* Clearance is more at low concentrations and less at high concentrationsQ.* Half-life is less at low concentrations and more at high concentrationsQ.* Very few drugs follow pure zero order kinetics e g. alcoholQ* Any drug at high concentration (when metabolic or elimination pathway is saturated) may show zero order kineticsQ.
A constant amount is eliminated in unit time
The half-life increases with an increase in dose
The rate of elimination is constant
The rate of elimination is proportional to the plasma concentration
Pharmacokinetics