Dosresponssättning

Dosresponssättning, or dose–response relationship, is a concept used in pharmacology, toxicology, and environmental health to describe how the magnitude or probability of a biological effect changes with the amount of exposure to a substance. The dose refers to the amount of a chemical encountered by an organism, often normalized to body weight, while the response is the measurable effect, which can be a physiological change, a symptom, or an adverse outcome.

There are two broad types of dose–response relationships. Graded responses describe continuous changes within individuals, such as a gradual change in blood pressure with increasing drug dose. Quantal responses describe outcomes that occur or do not occur across a population, such as death or recovery, and are often summarized as proportions of affected individuals at each dose.

Common models include sigmoidal dose–response curves described by the Hill equation for graded effects, which yields parameters such as Emax (maximum effect) and EC50 (dose producing half-maximal effect). For population-based data, probit or logit models are used to estimate the probability of response at each dose, producing metrics like ED50 (effective dose) and LD50 (lethal dose).

Key concepts include potency (the dose needed to achieve a given effect), efficacy (the maximum achievable effect), and thresholds (a dose below which no adverse effect is observed, often contrasted with no-threshold models in risk assessment). Regulatory work often uses NOAEL and LOAEL, or benchmark dose approaches, to summarize dose–response data.

In risk assessment, dose–response relationships support extrapolation from experimental or observational data to human health risk, informing exposure guidelines. Challenges include interspecies differences, population variability, and uncertainty at low doses, which influence model choice and precautionary factors.