1. Dose-response curves

2. Dose is plotted on the horizontal axis and response on the vertical axis. The slope of the dose –response curve defines the extent to which a desired response alters as the dose is changed.

3. Types of dose-response curve: 1-quanted dose-response curve it is an all-or-none response to a drug and relates to the frequency with which a specified dose of drug produces a specific response in a population ( in contrast to graded curve, quanted curve rapidly reaches a plateau).

4. dose
response

5. 2- graded dose-response curve is a steep-rising and prolonged curve indicates that a small change in dose produces a large change in drug effect over a wide dose range e.g. loop diuretic furosemide used in dose from 20 mg – 250 mg/day.

6. drug A
drug B
Emax
dose
response

7. 3- Log dose-response curve it is a sigmoidal graded dose response curve, plotted between the log of the dose and the drug effect. Dose-response curves may be constructed for wanted effects and also for unwanted effects.

8. response log of the dose drug A drug B Emax A Emax B ED50 for drug B
ED50 for drug A
ED50 for drug B