drug molecules move in ____ ____ motion, _____ then ______ the bond and then ______ again according to the _______ of the molecule and _______ from other drug molecules
constant random
binding
releasing
binding
affinity
competition
t/f drug molecules move in constant organized motions
false constant random
what affects the binding of a drug molecule to a receptor?
affinity of the molecule
competition from other drug molecules
what type of chemical bond is weak and easily reversed?
ionic bonds
what type of chemical bonds are weaker than ionic
hydrogen bonds
what type of chemical bond is often irreversible and is the strong bond? give an dental example
covalent bonds
tetracycline + dentin
what chemical bond contributes to mutual attraction between molecules
van der Waals forces
what are the two most common bonds between drugs and receptors? why?
hydrogen and ionic
because they are easily reversed
t/f hydrogen and ionic bonds are the most common bond between drugs and receptors because they are irreversible and the strongest
FALSE-they are the most common because they are easily reversed
The most common type of chemical bond
between a drug molecule and receptor is
1) Hydrogen bond
2) Covalent bond
3) Ionic
4) van der Waals forces
D) 1 and 3
Hydrogen binding and ionic binding are the most common types of binding between drugs and receptors
good affinity is directly related to greater _____
potency
____ dose and _____ dose are both related to their chemical structure
ceiling dose
threshold dose
what is the maximum response produced by a drug called?
ceiling dose
what is the lowest dose to produce an effect called?
threshold dose
efficacy is related to the _____ ____ of the drug once a drug receptor complex is formed
intrinsic activity
The term that describes the maximum response produced by a drug is:
E) Potency
C) Efficacy
Efficacy is the magnitude of response obtained from optimal receptor site occupancy by a drug
a competitive antagonist as affinity but no intrinsic activity what effect does it have on the agonist?
reduces the potency of the agonist
toxicity can occur because of undesirable effects associated with administration of _______ dosages of drugs
therapeutic
what are some undesirable effects associated with administration of therapeutic dosages of drugs?
exaggeration of direct effects at higher dosages
multiple concurrent adverse effects at therapeutic dosage level
toxicity can occur in two ways what are they?
overdose or side effect
what is used during drug development to identify safe and effective doses?
therapeutic index or TI
t/f the lower the numeric value of the TI the safer the drug
false- the HIGHER the number the safer the drug
what is the ratio used to figure the TI?
ratio of LD50 and ED50
Two similar drugs (A and B) are being compared. The therapeutic index (TI) is computed for both of them. The TI for drug A is 8.5, and the TI for drug B is 5.0. Which drug is relatively more safe?
information
B) Drug A
The therapeutic index is used to compare the relative
safety of a drug. The higher the numeric value, the safer the drug.
what is the movement of drugs through the body called?
pharmacokinetics
what five things does pharmacokinetics relate to?
drug's absorption
distribution in the body
distribution to site of action
Metabolism of drug
Excretion of drug
what are the six factors influencing the rate of absorption?
degree of ionization and pH of tissues
formulation of the drug (liquid or solid form)
drug concentration
degree of blood circulation to the area
area of absorptive surface (larger area more absorption)
rout of drug administration (enteral or parenteral)
the six factors influencing the rate of absorption are: degree of _______ and ____ of tissues, ______ of the drug (liquid or solid form), drug ______, degree of blood _______ to the area, ______ of absorptive surface, _____ of drug ________ (enteral or parenteral)
ionization and pH
formulation
concentration
circulation
area
route
administration
t/f nonpolar, nonionized drugs will cross biologic membrane easier
true
what is the purpose of the enteric coating? (3)
delay dissolution of drug in the stomach, so that it will dissolve in the upper intestines instead of the stomach and reduces the adverse gastric side effects
a greater concentration of the same drug means it will _____ faster than a lower concentration
absorb
greater blood flow to an area = ?
faster rate of absorption
what organs have the greatest blood circulation?
liver
heart
GI tract
where is the site of absorption for most oral drugs?
upper small intestine
what route is the safest most common, convenient and most unpredictable?
oral (enteral)
what effect may reduce concentration of drug molecules (hint the liver breaks it down first)
first pass
the _____ metabolizes most of the drug and the concentration is reduced this is called what?
liver
first pass
what route of administration is the most predictable?
IV route
where does the majority of metabolism occur?
liver
t/f the majority of metabolism occurs in the upper small intestines
false-liver
what are the enzymatic reactions known as phase I and phase II known as?
biotransformation
biotransformation can alter drugs 4 ways what are they? (4 conversions)
convert active drug into inactive drug
convert active drug to an active drug or toxic metabolite
convert inactive drug to active drug
convert unexcretable (more lipophilic) drug into excretable (more hydrophilic) metabolite
which phase is it when the chemical structure is modified through oxidation, reduction or hydrolysis
phase I
what phase is it when it changes the drug so it is not active
phase II
what is responsible for many adverse drug reactions?
cytochrome P450
what is the most common means to eliminate drug molecules?
renal excretion
where in the kidney does excretion take place?
glomerularis
what are the two types of glomerular filtration?
active tubular secretion
passive tubular reabsorption
how many half lives are there to eliminate a drug?
4
what is zero order kinetics?
constant amount eliminated per unit of time
t/f a constant fraction of the drug is eliminated per unit of time
true
The enzymatic reactions, classified as phase I and phase II processes, are known together as:
B) Biotransformation
Biotransformation is the set of enzymatic reactions that can convert an active drug to inactive, an active drug to metabolite, an inactive drug into an active drug, or an unexcretable drug into an excretable metabolite
