doseréponse

Doseréponse, commonly referred to in English as dose–response, is the relationship between the amount of a substance and the magnitude of the biological or health effect it produces. It is a central concept in pharmacology, toxicology, and risk assessment, used to characterize how exposure translates into effect and to guide dosing and safety decisions.

There are two main forms of dose–response relationships. Graded dose–response describes a continuous change in effect within a single organism as the dose changes. Quantal dose–response describes an all-or-none outcome across a population, such as the proportion of individuals who exhibit a toxic effect at each dose. Graded responses are often sigmoidal, rising with dose toward a maximum effect, while quantal curves summarize population-level responses.

Models and metrics commonly used include the Hill equation and the Emax model for graded responses. Key parameters include the EC50 or ED50, the dose that produces 50% of the maximal response, and Emax, the maximum achievable effect. In toxicology, LD50 (lethal dose for 50% of subjects) and TD50 (toxic dose for 50%) are frequently cited. Potency and efficacy describe, respectively, the amount of dose needed for a given effect and the maximum effect attainable.

Doseréponse is influenced by pharmacokinetics (absorption, distribution, metabolism, excretion), pharmacodynamics (receptor interactions), and factors such as genetics, age, health status, and co-exposures. Non-monotonic and hormetic dose–response patterns can occur, complicating interpretation.

Applications include drug development, safety testing, exposure assessment, and regulatory standards such as no observed adverse effect level (NOAEL), reference doses, and benchmark dose analyses. Limitations include interspecies differences, variability among individuals, and extrapolation challenges from short-term studies to long-term outcomes.