Flashcards in Pharmacology Lecture 1 Deck (32)
what factors affect Fick's law of diffusion?
area and thickness of membrane
what is a weak acid drug?
neutral -> protonated + H+
what is a weak base drug?
protonated -> neutral + H+
what form of a weak acid or base is the lipid soluble form?
unprotonated (neutral form)
which form of drug can easily diffuse through the kidney tubule?
lipid soluble (unprotonated)
how would you adjust urine pH to excrete a weak base drug?
make it more acidic (moves drug to the protonated form and can't pass through tubule)
how would you adjust urine pH to excrete a weak acid drug?
make it more basic (moves drug to the protonated form and can't pass through tubule)
what is a chemical antagonist?
when one drug binds with another drug in the blood stream thereby prohibiting action of either drug
what is a physiologic antagonist?
when an antagonist acts on a different receptor but opposes another pathway
what are pharmacokinetics?
absorption, distribution, metabolism and excretion of a drug
(what the body does to the drug)
what are pharmacodynamics?
non-receptor or receptor mechanisms
(what the drug does to the body)
what is an additive affect?
when two drugs have to work together to make an effect?
2+2 = 4
what is synergistic?
when two drugs working together make a better effect
2 + 2 = 4 + 4
what is potentiation?
when one drug improves the performance of another drug
2+ 2 = 4 + 2
in the case of a contraindication you would...
never ever ever give the drug
what do agonists have that antagonists do not?
-they only have affinity
what kind of bond does a competitive irreversible antagonist form?
what is the weakest type of bond?
van der waals
what process determines time of activity of G-protein?
hydrolysation of G protein from GTP to GDP diphosphate
what is tachyphylaxis?
loss of receptor function
what is down regulation?
receptors are removed and sequestered from the cell surface
loss of # of receptors
what are the three non-receptor mediated desensitizations?
1. reduction of coupling responses
2. increased metabolic degradation
3. opposing homeostatic response
what is constitutive activity?
receptor is not bound by a ligand but is causing an affect
what is an inverse agonist?
binding to the receptor site causes the constitutive activity to shut off
-it is an agonist because it is doing the activity of turning the activity off
what is Kd?
dissociation equilibrium , # of ligands going on = # of ligands dissociating
what is the relationship between affinity and Kd and concentration of drug?
inc. affinity = dec Kd and dec of drug concentration
which way does potency shift on a graph?
to the left
how do you calculate therapeutic index?
Toxic ED (TD50) / Beneficial ED50
many spare receptors will do what to the amount of drug needed?