Study Set Content:
differing substrate specificities of the multiple protein
kinases regulated by second messengers provide branch
points in signaling pathways that may be independently
regulated.
Flexible Regulation
When faced with a patient who needs treatment, the prescriber
must make a choice among a variety of possible drugs and devise a
dosage regimen that is likely to produce
maximal benefit and
minimal toxicity.
To choose among drugs and to determine appropriate doses of a
drug, the prescriber must know the relative pharmacologic
potency and maximal efficacy of the drugs in relation to
the desired therapeutic effects.
Graded Dose-Response Relations
refers to the concentration (EC 50) or dose
(ED 50) of a drug required to produce 50% of that drug's
maximal effect.
Potency
The clinical effectiveness of a drug depends not on its potency (EC
50 ), but on its (blank) and its ability to reach the relevant
(blank)
maximal efficacy, receptors.
This ability can depend on its
route of administration, absorption,
distribution through the body, and clearance from the blood or site
of action.
In deciding which of two drugs to administer to a patient, the
prescriber must usually consider their relative(blank)rather
than their relative potency.
effectiveness
can largely determine the administered dose
of the chosen drug.
Pharmacologic potency
For therapeutic purposes, the potency of a drug should be stated in
(blank), usually in terms of a particular therapeutic end point
dosage units
Drugs A, C, and D in Figures 2-15
have equal maximal efficacy and all have greater maximal
efficacy than drug B. The maximal efficacy (sometimes
referred to simply as efficacy) of a drug is obviously
crucial for making clinical decisions when a large response
is needed.
Maximal Efficacy
Extremely steep dose-response curves (eg. Curve D) may have
important clinical consequences if the upper portion of the curve
represents an (blank) of response
undesirable extent
Steep dose-response curves inpatient can result from cooperative
interaction of several different actions of a
drug
For example, such curves may be impossible to construct if the
pharmacologic response is an either-or
quantal event
For example, such curves may be impossible to construct if the
pharmacologic response is an either-or (quantal) event, such as
prevention of
convulsion, arrhythmia, or death.
Furthermore, the clinical relevance of a quantitative dose-response
relation in a single patient, no matter how precisely defined, may be
limited in application to other patients, owing to the great (blank)among patients in severity of disease and responsiveness.
potential
variability
The quantal dose-effect curve is often characterized by stating the
(blank), which is the dose at which 50% of
individuals exhibit the specified quantal effect.
median effective dose (ED50)
the dose required to produce
a particularly toxic effect in 50% of animals.
Median Toxic Dose (TD 50)
if the toxic effect is the death
of the animal.
Median Lethal Dose (LD 50)
Thus, if the ED 50s of two drugs for producing a specified quantal
effect are 5 and 500 mg, respectively, then the first drug can be
said to be (blank) more potent than the second for that particular
effect.
100 times
may be used to generate information
regarding the margin of safety to be expected from a particular
drug used to produce a specified effect
Quantal dose-effect
