Answer Happy

You need to look at drugs individually ie Drug A is
different from Drug B. All the values are given under normal
values. You need to observe what will happen to those values in
different scenarios, in this case situations. ie for Drug A
inhibitor of renal secretion.
Question 1 (16 marks) Normal values for the pharmacokinetic
parameters clearance, fraction unbound, and fraction excreted
unchanged are listed in the table for drugs A through E. Situations
are presented which alter the kinetics of each of these drugs. On
the right indicate whether the value of each parameter would be
observed to increase , decrease or show little or no change. All
drugs are administered orally and have volumes of distribution
greater than 50 litres. Assume GFR is 7.2 L/hr and QH is 90
L/hr.
Drug
Normal Values
Situations
Observation
Systemic
Clearance (L/hr)
Fraction Unbound in Blood
Fraction Excreted Unchanged in Urine
Systemic Clearance
Volume of Distribution
Half-life
Bioavailability
A
3.5
0.9
0.95
Simultaneous administration of a competitive inhibitor of renal
secretion
decrease
No change
increase
No change
B
80
0.5
0.02
Simultaneous administration of an inducer of metabolism
C
1
0.02
0.1
Simultaneous administration of a drug that displaces drug D from
plasma proteins
D
3
0.1
0.05
Administration of an enzyme inhibitor for several days