L9 Pharmacokinetic parameters

Question 1

I. pharmacokinetics

Answer 1

1. Absorption
2. Distribution
3. Metabolism
4. Excretion

Question 2

……………….. assumes primary importance in oral, inhalation, and dermal exposures.

Answer 2

Absorption

Question 3

The two kinetic parameters of concern are:

Answer 3

1- The rate of absorption
2- The extent of absorption (or bioavailability).

Question 4

is a measure of the body’s ability to completely clear a drug from blood.

Answer 4

Clearance(CL):

Question 5

Clearance is the rate of …………….

Answer 5

excretion

Question 6

CL = ………………………………………..

Answer 6

Rate of elimination of drug / Plasma drug conc.

Question 7

The time taken to reduce the plasma drug concentration by half:

Answer 7

Half-Life (t1/2)
(t1/2)= (0.693) x (v) over CL
• V= Volume of distribution
• CL= Clearance

Question 8

………. does is an ………. ……… ………. of a drug given at the onset of therapy if a therapeutic concentration must be achieved rapidly.

Answer 8

Loading, initial high dose

Loading dose (LD) = (v) x (Desired C) over F

• V= VOLUME OF DISTRIBUTION • F= BIOAVAILABILTY

Question 9

…………… dose is the dose of the drug required per unit time to maintain a desired steady state level in plasma to sustain a specific therapeutic effect

Answer 9

Maintenance

Maintenance dose ( MD) = (Desired Css) x (CI) over F
•CL= CLEARANCE
•F= BIOAVAILABILTY

Question 10

A normal volunteer will receive a new drug in a phase I clinical trial. The clearance and volume of distribution of the drug in this subject are 1.386 L/h and 80 L, respectively. The half-life of the drug in this subject will be approximately…………….

Answer 10

• t1\2= 0.693X 80 L / 1.386 L/h
• = 40 HR

Question 11

Estimate the oral loading dose of digoxin for a 70 kg man, which would be necessary to attain a plasma level of 1.5 μg/L (microgram/L)?
Vd of digoxin is 420 L, F for tablet is 0.62.

Answer 11

• Oral Loading Dose= 420 L X 1.5 μg/L / 0.62
• = 1016.129 μg
• = 1.016 mg

Question 12

Estimate the IV loading dose of a drug, which would be necessary to attain a plasma level of 2 μg/L (microgram/L)?
Its Vd is 100 L, F for iv is one.

Answer 12

• Loading Dose= 2 X 100 = 200 microgram

Question 13

……………. ……………… is the process that side effects of drugs are misdiagnosed as symptoms of another problem, resulting in further prescriptions and further side effects and unanticipated drug interactions, which itself may lead to further symptoms and further misdiagnoses.

Answer 13

Prescription cascade

Question 14

is the use of numerous medications at the same time.

Answer 14

Polypharmacy

Question 15

POLYPHARMACY MORE THAN .. ………….. AT THE SAME TIME

Answer 15

5 MEDICATION