You have seen that intrinsic efficacy describes the strength of a single drug-receptor complex's ability to evoke a response.
However, you will also encounter the term "efficacy".
Efficacy is a measure of a drug's ability to evoke a response in a tissue. It is a function of factors such as:
- The total number of receptors for that drug present in the tissue
- The type of coupling that exists between the receptor and the response
- The intrinsic efficacy of the drug at the receptor
Efficacy can take a value of between 0 and 1,
the higher the value, the stronger the response evoked.