What is meant by 'steady state' in pharmacokinetics?

The concept of 'steady state' in pharmacokinetics refers to the condition where the rate of drug administration equals the rate of elimination. At this point, the overall concentration of the drug in the blood or tissues remains relatively constant over time, meaning that the amount of drug entering the system is balanced by the amount being metabolized or excreted. Achieving a steady state is crucial for maintaining the desired therapeutic levels of a drug, ensuring its effectiveness while minimizing toxicity.

Understanding that steady state is not dependent on the peak effects of the drug, the phase where a drug loses efficacy, or simply the concentration of the drug in tissues is important. These concepts relate to other aspects of pharmacokinetics but do not define the steady state condition.