Konorev: Intro to Pharmacodynamics Flashcards
Pharmacokinetics
-the effects of the body on drugs
Pharmacodynamics
-effects of the drugs on the body
In a dose response curve, what two phases are there?
- linear phase
- Plateu phase
- hyperbolic curve
How do we change the hyperbolic curve into a sigmoid curve?
- change the x axis to log of dose rather than just dose
- extends the linear phase
What id ED50? (effective dose 50)
-the dose of drug that produces 50% of its maximal effect
Affinity
-describes how readily and tightly that drug binds to its receptor
What is KD
- equilibrium dissociation constant
- drug concentration at which 50% of the drug receptor binding sites are occupied by the drug
- lower Kd= higher affinity, and vice versa
Drug selectivity
- determined by drug’s affinities at various binding sites
- more selective drug would affect fewer targets
Intrinsic activity
- describes the ability of a drug to change a receptor function and produce a physiological response upon its binding to a receptor
- Example: agonists, but not antagonists
Do antagonists change the function of the receptor upon binding?
- no
- there is no intrinsic efficacy
What happens to EC50 and Emax with competitive antagonism?
- agonist EC50 increases
- Emax does not change
What happens wto EC50 and Emax with noncompetitive antagonism?
- agonist EC50 does not change
- Emax decreases (lower ceiling)
How do you find Kd?
- equilibrium dissociation constant
- (L)(R)/(LR)
Which drug will have a higher Emax, a partial agonist or a full agonist?
-a full agonist will have a bigger Emax than the partial agonist
can a partial agonist cause an opposite effect in the presence of a full agonist?
- yes, so watch out for that
- ex: pindolol
- increases HR when used alone, but in the presence of full agonist, it decreases HR
What happens with the receptor when an antagonist binds?
-nothing happens to the receptor, it just gets blocked
what is potency related to?
- drug dose
- a lower dose will activate a receptor better
- describes the amoint of drug required to porduce a specific pharmacological effect
What is efficacy related to ?
- Bmax
- the number of available receptors available to bind a drug
- the maximal pharmacologic effect that a drug can produce
What is a graded response?
- answers the question “How Much?”
- typically represents the mean value within a population or a single subject
- sigmoidal curve
What is a quantal response?
- all or none, yes-no, binary responses
- “does the response occur or not?”
- “in how many?”
- used to examine the frequency of a response within a large population
- bell shaped curve if non cumulative
- cumulative will be sigmoid
What is a cumulative quantal dose response curve?
-number or % of ppl responding at a dose of a drug and at all doses lower than that dose
How do we find therapeutic index?
- TD50/ED50
- the higher the TI, the safer the drug
What is the therapeutic window?
-the range of doses of a drug or of its concentration in a bodily system that provides safe and effective therapy
What can we find froma cumulative frequency distribution?
-Median effective dose (ED50
