Study Set Content:
may be anticipated when there is
major impairment of the function of the kidney, liver,
or heart.
Abnormal clearance
is a useful quantitative indicator
of renal function.
Creatinine clearance
Conversely,(blank) may be a useful indicator
of the functional consequences of heart, kidney, or
liver failure, often with greater precision than clinical
findings or other laboratory tests.
drug clearance
For example, when
renal function is changing rapidly, estimation of the
clearance of(blank) may be a
more accurate indicator of glomerular filtration than
serum creatinine.
aminoglycoside antibiotics
Normal values of creatinine clearance for women:
1.4
If it is more than 1.4 it is an early sign that your kidneys are
not working properly.
reflects a
balance between binding to tissues,
volume of distribution
The apparent volume of distribution reflects a
balance between binding to tissues, which decreases
plasma concentration and makes the apparent
volume
larger
The apparent volume of distribution reflects a
balance between binding to tissues, which decreases
plasma concentration and makes the apparent
volume larger, and binding to plasma proteins,
which increases plasma concentration and makes
the apparent volume
smaller
For example, the half-life of diazepam increases with
patient age
When clearance is related to age, it is found that
clearance of this drug does not change with
age
The increasing half-life for diazepam actually results
from changes in the volume of distribution with age;
the metabolic processes responsible for eliminating
the drug are fairly
constant
All pharmacologic responses must have a (blank) No matter how high the drug
concentration goes, a point will be reached beyond
which no further increment in response is achieved.
maximum
effect (E max ).
If increasing the dose in a particular patient does not
lead to a further clinical response, it is possible that
the maximum effect has been
reached
Recognition of maximum effect is helpful in avoiding
ineffectual increases of dose with the attendant risk
of
toxicity.
The sensitivity of the target organ to drug
concentration is reflected by the concentration
required to produce 50% of maximum effect, the
C50
Diminished sensitivity to the drug can be detected by
measuring drug concentrations that are usually
associated with therapeutic response in a patient
who has
not responded
This may be a result of abnormal physiology, eg,
hyperkalemia diminishes responsiveness to
(blank)—or drug
digoxin
the single most important factor
determining drug concentrations.
Cleaarance
THREE FACTORS THAT MAY INFLUENCE CLEARANCE:
1. dose
2. organ blood flow
3. intrinsic function of the liver or kidneys
