Dose-Response Relationships Flashcards
What does the dose-response relationship describe?
the biological response/effects of drugs/toxins
receptor occupancy and response
- most physiological systems the response in non-linear with full response being observed before receptor saturation
- the remaining receptors above maximum response are “spare” receptors
Graded response
- gradual
- continuous
- useful in analyzing biological response to an incremental change in the amount of a drug used
Quantal response
- response either occurred or didn’t (no in between)
- useful in determining dose ranges and therapeutic indexes that are effective/safe for the patient population
Graded dose-response curve
- relationship between drug concentration and biological effect
- Emax
- EC50
Emax
the maximum biological effect of the drug
EC50
- half maximal effective concentration
- concentration needed to achieve half of maximum efficacy
Semi-log plots
- use is typically employed to analyze dose-response over several orders of magnitude
- easier to compare similar compounds
Threshold dose
the dose that is required to obtain a measurable effect
Slope of dose response curve
denotes the rate at which dose effects response
steep slope - small increase in dose has large effect on response
potency
amount of drug necessary to achieve a response of a given magnitude
Efficacy
aka intrinsic activity
ability of a drug to elicit a particular biological response
Competitive agonist and dose response curve
- shift to right
noncompetitive antagonist and dose response curve
- curve goes down
TD50
produces a toxic effect in half the patient population
