1. Dose response relationships can be represented by either graded or quantal curves, with graded curves showing a continuous response to varying doses and quantal curves showing the proportion of subjects responding at different doses. 2. Key features of dose response curves include the median effective dose (ED50) which produces a 50% response, potency which is measured by the dose required for 50% effect, and the therapeutic index which is the ratio of toxic to effective doses. 3. Both curve types provide information about a drug's potency but graded curves also indicate maximum efficacy while quantal curves show variability in individual responses.

1. Dose Response Relationship & Therapeutic Index Dr Rizwan

2. quantal (cumulative) D/R curve tachyphylaxis graded (quantitative) D/R curve therapeutic index potency median toxic dose (TD50) efficacy (effectiveness) median effective dose (ED50) dose/response (D/R) Objectives

4. Systemic description of the magnitude of the effect of a drug as a function of the dose (very low to very high)

10. BIOLOGICAL STIMULUS PERCENT RECEPTOR OCCUPANCY 0% 100% BIOLOGICAL RESPONSE RECEPTOR RESERVE TRETHOLD 0% 100% Max Effect Threshold Effect Schematic representation of the relationship between threshold, receptor reserve, receptor occupancy, biological stimulus and biological response

22. POTENCY CONCENTRATION (EC50) OR DOSE (ED50) OF A DRUG REQUIRED TO PRODUCE 50% OF THAT DRUG’S MAXIMUM EFFECT

25. [D] (concentration units) % Maximal Effect 0.01 0.10 1.00 10.00 100.00 1000.00 0.0 0.2 0.4 0.6 0.8 1.0 Partial agonist Full Agonist Partial agonist PARTIAL AGONISTS - EFFICACY Even though drugs may occupy the same # of receptors, the magnitude of their effects may differ.

32. What is the difference between Quantal and graded dose-response curves?

34. Graded dose response curves show effects on a continuous scale And the intensity of the effect is proportional to the dose

35. Exposure to ethanol Graded responses between no effect and death

38. Plot of the contraction of the intestinal smooth muscle in response to varied doses of acetylcholine

52. BELL SHAPED CURVE majority of responders in the middle mean response is approx. 110 mg/kg fewer responders at the end of bell curve (expected) known as biological variability responders at the far left of the mean are typically hypersusceptible whereas those at the far right are resistant

56. Cumulative quantal dose response plot

63. BIOLOGICAL STIMULUS PERCENT RECEPTOR OCCUPANCY 0% 100% BIOLOGICAL RESPONSE RECEPTOR RESERVE TRETHOLD 0% 100% Max Effect Threshold Effect Schematic representation of the relationship between threshold, receptor reserve, receptor occupancy, biological stimulus and biological response