To define and explain dose-effect relationships of drugs, including dose-response curves with reference to: graded and quantal response.
Standard Dose-Response Curves
A dose-response curve is a graph of concentration against the fraction of receptors occupied by a drug.
Log-Dose Response Curves
It is difficult to compare drugs using standard dose-response curves. Therefore, dose is commonly log-transformed to produce a log-dose response curve.
- Compares log-dose versus clinical effect
- Demonstrates that the blue drug has greater potency than the red drug, though both are full agonists
Responses can be either graded or quantal:
- Graded responses demonstrate a continuous increase in effect with dose
- E.g. Blood pressure and noradrenaline dose
- Quantal responses demonstrate a response once a certain proportion of receptors are occupied
Median dose of neuromuscular blocker required to produce a 95% loss of twitch height.
Mean alveolar concentration of agent required to prevent movement in response to a surgical stimulus.
- Anderson C. Pharmacodynamics 1. ICU Primary Prep. Available at: https://icuprimaryprep.files.wordpress.com/2012/05/pharmacodynamics-1.pdf