The process involved in the removal of drugs from plasma is primarily elimination. This encompasses both the metabolic conversion of the drug and its subsequent excretion from the body. While metabolism refers specifically to the biochemical transformation of the drug into different compounds (often resulting in metabolites), elimination includes the total process of reducing the concentration of the drug in the plasma.
Elimination effectively combines both the metabolic processes that alter the drug and the physical removal of these compounds, typically through excretion routes such as urine or bile. Therefore, considering the overall context of the drug clearance from the bloodstream, elimination accurately captures the entirety of the process involved in drug removal.
Distribution, on the other hand, pertains to the dispersion of the drug throughout the tissues and organs rather than its removal from the bloodstream. Metabolism focuses specifically on chemical changes to the drug, while excretion involves the actual removal process but is only one part of the broader elimination process.