Principles of Drug Action Flashcards
Some consequences of poor drug therapy
No therapeutic benefit Side effects Poor compliance Drug interactions Drug resistance
what are the main objectives of drug therapy?
Get the right drug
in the right space
at the right concentration
for the right period of time
what is pharmacodynamics?
Mechanism of action (molecular target and physiology), dosing, side effects
what is pharmacokinetics?
ADME
-absorption, duration, metabolism and excretion
what are the X and Y axises in a dose-response curve?
x=dose
y=response
what is EC50?
effective concentration to produce 50% of maximal response (measure of potency)
what is the difference between EC50 and ED50?
ED 50 uses the DOSE of drug producing 50% of maximal response to compare potencies rather than concentration
what is IC50?
inhibitory concentration
What is TD50?
toxic dose
What is LD50?
lethal dose
what is efficacy?
the level of effect a drug elicits
what is potency?
the amount or concentration of a drug responsible for a response
(high potency = big effect from small amount)
when comparing potency, what values can you compare?
ED50
what does the therapeutic index quantify?
quantifies side-effects
name a drug that has no side effects
there isn’t one
what causes side effects?
Most side effects are mechanism based
- Due to therapeutic mechanism of action
- Due to off-target mechanism of action
- Due to interaction/interference with other drugs (competition)
- Often, but not always, dose-dependent
what are some common side effects of anesthesia?
Nausea and vomiting Cognitive dysfunction Muscle ache/fatigue Itching sensations Emotional reactions
which drug often creates the effect? bound or free?
the free drug
for a therapeutic index, the _____ the ratio, the safer the drug
larger
what are some main mechanisms of drug action?
Act directly or indirectly on receptors, channels, transporters or enzymes;
Act competitively or irreversibly
Mimic or antagonize endogenous substances
Drugs and drug target can be pleiotropic (effect many parts) or very specific
Can impair key point(s) in a metabolic chain to collapse the whole
