Study Set Content:
This can be conveniently estimated from
the creatinine clearance, calculated from a single
(blank) measurement and the predicted
(blank)
serum creatinine , creatinine production rate.
The predicted creatinine production rate in women is
(blank) of the calculated value, because they have a
smaller muscle mass per kilogram and it is muscle
mass that determines creatinine production.
85%
Muscle mass as a fraction of body weight decreases
with age, which is why age appears in the
Cockcroft-
Gault equation.
Sr Creatinine
insensitive marker
Needs to be corrected for age, gender, weight, and muscle mass
Cockcrot-Gault Equations
Cret Clearance = (140-age)X weight/72 x Sr Creat
The decrease of renal function with age is
(blank) of the decrease in creatinine
production.
independent
Because of the difficulty of obtaining complete urine
collections, creatinine clearance calculated in this
way is at least as reliable as estimates based on
urine collections
should be considered rather than
total body weight for obese patients,
fat-free mass
The fat-free mass should be considered rather than
total body weight for obese patients, and correction
should be made for (blank) in severely ill
patients.
muscle wasting
The common sense approach to the interpretation of
drug concentrations compares predictions of
(blank) and expected
concentrations to measured values.
pharmacokinetic parameters
If measured
concentrations differ by more than (blank) from
predicted values, revised estimates of V or CL
20%
V =
V =Amount of drugs in the body/C
CL
CL = Rate of Elimination/C
If the change calculated is more than a 1(blank) in either V or CL, the
assumptions made about the timing of the sample
and the dosing history should be critically examined.
100%
increase or 50% decrease
Constant fraction of drug eliminated per unit of time
First order
Constant amount of drug eliminated per unit time
Zero order
The rate of drug elimination proportional to drug plasma concentration
First order
Rate of drug elimination independent of drug plasma concentration
Zero order
