In pharmacology, the term "ceiling effect" is used to describe the effect when, despite an increase in dose, there is no further increase in the effect of a drug. In other words, the dose-response curve reaches a maximum before the maximum effect of a drug (efficacy) is reached.
The ceiling effect is clinically relevant in the case of:
A ceiling effect occurs when an active substance has already occupied the number of receptors required for its maximum effect. The maximum of the dose-response curve has then been reached and increasing the dose no longer leads to a stronger effect, but possibly only to stronger side effects.
The ceiling effect is independent (!) of the frequency and duration of the drug application (see also in contrast: tolerance/tachyphylaxis - effects that occur with repeated application of a drug).