doseffekt

Dose-effect, or dose–response relationship, in pharmacology describes how the intensity of a drug's effect changes with dose. It can refer to graded responses (continuous intensity) or quantal responses (events versus no events).

Typically, the dose–response curve is sigmoidal; at low doses the effect is small, then it rises steeply as the dose increases, and finally plateaus as receptors saturate. Key terms include potency (the dose required for a given effect) and efficacy (the maximum effect a drug can produce). The ED50 or EC50 are common measures of potency, while the maximal effect is the ceiling of the curve.

Determinants of the dose-effect include pharmacodynamics and pharmacokinetics. Pharmacodynamics concerns receptor occupancy and intrinsic activity; pharmacokinetics covers absorption, distribution, metabolism, and elimination, influencing the actual dose reaching the site of action. Individual factors such as age, body weight, genetics, disease state, and drug interactions also shape the dose-effect. Tolerance or sensitization can shift the curve over time.

Applications include determining dosing regimens, evaluating potency and efficacy during drug development, and estimating the therapeutic index (the ratio of TD50 to ED50) and safety margins. The dose–response framework helps predict benefits and risks, optimize treatment plans, and support regulatory decisions.

Limitations: real-world dose-effect can vary due to nonlinearity, multiple targets, or time-dependent changes. For toxicity, the dose–response curve informs risk assessment and public health decisions.