Pharmacokinetics (PK) is a branch of pharmacology dedicated to determining the chemical fate of substances in living organisms, from administration to elimination from the body. PK can be described as how an organism affects a drug, whereas pharmacodynamics (PD) is the study of how a drug affects the organism. Both PK and PD are described for each drug annotated in the Drug Absorption, Distribution, Metabolism and Excretion (ADME) pathways. For example, although paracetamol ADME (PK) is described in this section, the pharmacological inhibition (PD) of its targets (PTGS1 and PTGS2) is described in the relevant pathway where these enzymes perform their physiological duties. A connection is made between the two pathways to link PK and PD annotations.

The disposition of a pharmaceutical compound within an organism can be described by four main stages; absorption, distribution, metabolism, and excretion, abbreviated to ADME (Pallasch 1988, Ruiz-Garcia et al. 2008, Currie 2018). Sometimes, separate steps can be tacked on to ADME depending on what is being described. For example, where a drug is released from a pharmaceutical formulation, liberation (L) is added to ADME (LADME) or where the toxicity of a compound is described, T is added (ADMET).

ADME of various drugs is annotated in this section.