chapter2 pharmacodynamics Flashcards
Receptor function
- Determinants quanti relation2. Regulatory proteins3. Therapeutic and toxic effects
Emax
Maximal response produced by a drug
Ec50
50% maximal effect
Bmax
Total concentration receptor site. (ie. Sites bound to the drug infinitely high conc of free drug)
Kd
(Equilibrium dissociation constant)Conc free drug at which half maximal binding.⬇️ Kd : binding affinity is high⬆️ Kd : binding affinity is low
Coupling
Transduction process that links drug occupancy of receptors and pharmacologic respnse
Spare receptors
Possible to elicit MAXIMAL biological response at conc of agonist that doesnt result in occupancy of full complement of available receptorsEc50< Kd
Example spare receptors
Irreversible antagonist
90% quasi-irreversible antagonist
B- adrenoceptors
Types of antagonist
- Chemical 2. Functional3. Competitive A. Eq B. Nonequilibrium4. Noncompetitive
Antagonist property
+ affinity- efficacy
Other type of antagonism
PhysiologicalChemicalPharmacokinetic
Pharmacokinetic antagonist
One drug accelerates/ eliminates other drug
2 properties agonist
AffinityEfficacy
Comparative term for distinguishing which agonist has a higher affinity for given receptor
Potency
Response to low doses op a drug usually ⬆️ in direct proportion to dose
Dose-resp rel
Interaction of two agonist that act independently but cause opposite effects
FUNCTIONAL ANTAGONISM
Example func anatagonist
ACTHEPINEPHRINE
Eq competitive
Band is loose
Noneq competitive
Bond is covalent
PHARMACODYNAMICS
Study of rel drug conc and effects” DRUG does to the body”
PHARMACOKINETICS
what the body does to the drug
Examples of drugs of chem interaction
PROTAMINE SULFATE
MOA: membrane surfactants
Amphotericin B- antifungal grrr
MOA: denature proteins
ASTRINGENTS
Concentration range over which drug produces a - toxicity-effectivity- ineffectiveness
Therapeutic window
Cumulative distribution of a population response to a drug
Quantal dose
Uses of quantal dose
TD 50LD 50
TD 50
Dose produce a toxic effect in 50% of population
LD50
Dose that produce mortality in 50% of population in animal settings
Therapeutic index
Ratio of TD50 and ED50If ⬆️ = safer
Propranolol
Competitive B- adrenoceptor antagonist
2 therapeutic implication for competitive antagonist
- Conc of antagonist2. Conc of agonist in competition
Irreversible a- adrenoceptorControl HTN caused by catecholamine from pheochromocytoma ( tumor adrenal medulla
Phenoxybenzamine
Types of agonist
- Partial2. Full
Many clinical antagonist are actually
Weak partial agonist
Partial agonistu-opiod receptorsSafer analgesic drug than morphine coz of less RDS in overdoseEffective antianalgesic to morphine individual
Ibuprenorphrine
Inhibitors of tyrosine kinase for neoplastic do
TrastuzumabCeruximab
Other tyrosine inhibitors in the cytoplasm that are “small mol”
GefitinibErlotinib
Inhibits voltage gated channel in d ❤️ and vascular sm mm = antiarrhythmic effects, ⬇️ bp Without mimicking or antagonizing any known endogenous NT
Verapamil
Selective inhibitor type 3 phosphodiesterase that are expressed im cardiac mmAdjunctive agent tx acute heart failure
Milerinone
Inhibits phosphodiesterase ⬇️Interferes cGMP For the tx erectile dysfunc and pulmo HTN
Sildenafil
PhosphorylAtion: Common theme2 func
AmplificationFlexible regulation
Tx for breast ca that antagonizes GF receptor signaling
Trastuzumab
Small molecule inhibitor cytoplasmic tyrosine kinaseTx CML
Imatinib
Drug antagonist to the estrogen mammary receptor “ Agonist to the estrogen bone receptor Agonist in uterus which is stimulating endometrial cell proliferation.
Tamoxifen
Responsiveness diminish rapidly after administration of drug
Tachyphylaxis
A weak partial agonist at angiotensin II receptors:⬇️BP with px with HTN caused by increase angiotensin II production⬆️BP in px who produce normal amount of angiotensin
Saralasin