What are the four phases of pharmacokinetics?

Pharmacokinetics is the branch of pharmacology that studies how drugs move through the body over time. The four key phases of pharmacokinetics are absorption, distribution, metabolism, and excretion.

Absorption pertains to how a drug enters the bloodstream after administration, encompassing various routes like oral, intravenous, or intramuscular. Distribution refers to how the drug is dispersed throughout the body and how it travels to various organs and tissues. Metabolism involves the chemical alteration of the drug, primarily occurring in the liver, where it is transformed into metabolites that can be either active or inactive. Lastly, excretion is the process of eliminating the drug and its metabolites from the body, often through urine or feces.

This framework helps healthcare professionals understand the factors that influence drug action and effectiveness, including how quickly a drug takes effect and how long it remains active in the body. The other options either misidentify the phases or include inaccurate terminology that does not align with established pharmacokinetic principles.