Drug Therapy Flashcards
(25 cards)
increasing dose does not reduce the time at which peak concentration is reached? True or False
True
what is the therapeutic index
measure of the range at which a drug is safe and active
what is meant by the term bioavailability
amount of drug that has reached the circulation and is available for action
what is the bioavailability of a drug given intravenously
100%
what factors affect bioavailability
ability of drug to pass physiological barriers
first pass metabolism
slow release preparations
when a drug leaves the blood stream where can it go
intercellular spaces
intracellular spaces
if a drug is bound to a protein is it available for action
no
in water an acid will give up its protein to become what
its own conjugate base
in water a base will pick up a protein to become what
conjugate acid
for drugs to cross the cell membrane what property must they have
must be lipid soluble
are ionised or deionised drugs more lipid soluble
deionised drugs
acids are best absorbed in what kind of environment
acidic
bases are best absorbed in what kind of environment
basic
where does the metabolism of drugs usually occur
liver
can occur in the gut,kidney or lung lining
what is the purpose of metabolism
to increase water solubility and therefore aid excreation
what is the name given to drugs than become activated once metabolised
prodrugs
what is the purpose of phase 1 metabolism
to increase the polarity of the compound and provide an active site for phase 2 metabolism
5-10% of the population may be immune to the analgesic actions of codeine, why?
the enzyme responsible for the metabolism of codeine to morphine may be absent or reduced in some individuals
what happens in phase 2 metabolism
conjugation
what factors can effect metabolism
age
sex
ethnicity
pregnancy
what are some common enzyme inducers
alcohol
smoking
if drug metabolising enzymes are induced what effect does this usually have on the drug
results in decreased drug effect
what type of ADR is predictable
Type A- augmented
are type B ADR preventable?
no they are unpredictable reactions