Topic overview

Start with the big picture

Graded dose–response curves track the magnitude of an effect in a subject or system; quantal curves show the proportion of a population with a defined effect. Potency is associated with EC50, whereas efficacy refers to the maximum response, so the two describe different properties. Safety analysis also uses measures such as the therapeutic index and margin of safety, alongside threshold and observed adverse-effect levels. Curve slope and shape matter: steep slopes can make small dose changes consequential, and hormesis describes a biphasic response. Toxicokinetics applies ADME principles to poisons. Route, distribution, metabolic capacity, elimination, clearance, half-life, and overall exposure help explain systemic burden and how long toxicity may persist. These ideas support interpretation of risk and clinical course without replacing case-specific assessment.