About first-order kinetics, the true statement is
Clearance remains constant
Fixed amount of the drug is eliminated
Half life increase with dose
Decreased clearance with increasing dose
Most of the drugs follow 1st order kinetics in 1st order kinetics-clearance is constant and, elimination is not saturable, and the rate of drug elimination is directly propoional to the concentration. This is usually referred to as first-order elimination Reference: Katzung Pharmacology; 13th edition; Chapter 3; Pharmacokinetics & Pharmacodynamics: Rational Dosing & the Time Course of Drug Action
General anatomy