14. Pharmacokinetics

Question 1

ADME

Answer 1

Absorption Distribution Metabolism Excretion

Question 2

enteral routes of administration

Answer 2

Oral

Sublingual

Rectal

Question 3

parenteral routes of administration

Answer 3

Subcutaneous

Topical

ID

IM

IV

IA

Nasal

Question 4

First-pass metabolism

Answer 4

Extensive drug metabolism occurs in the liver

low proportion of oral dose reaches systemic circulation

drug has low oral bioavailability

Question 5

Exponential elimination of a drug

Answer 5

Question 6

The distribution of a drug between plasma and the rest of the body after dosing and is dependent on

Answer 6

drug permeability across membranes

binding within compartments

pH partition

Question 7

Phase I metabolism

Answer 7

Oxidation (reduction and hydrolysis)

cytochrome P450 enzymes

P450 inhibitors

Question 8

Phase II metabolism

Answer 8

Conjugation reactions

Question 9

Half-life

Answer 9

Time for the plasma concentration of the drug to halve

Question 10

Routes of drug excretion

Answer 10

kidneys

hepatobiliary system

lungs (volatile anaesthetics)

glandular secretions (quantitatively negligible)

Question 11

First-order kinetics

Answer 11

plasma drug levels decline at a rate directly proportional to plasma level

Question 12

Zero-order kinetics

Answer 12

drug levels decline at a constant linear rate independent of plasma concentration

Question 13

Maintenance dose

Answer 13

Clearance x desired Css

Question 14

Loading dose

Answer 14

Vd x desired Css

Question 15

Steady state concentration (Css)

Answer 15

Bioavailability x Dose / Intervaldosing x Clearance

Question 16

Volume of Distribution

Answer 16

Dose (D) / [drug]plasma

Question 17

Half-life calculation

Answer 17

0.693 / Kel (elimination rate constant)

Question 18

Clearance

Answer 18

Kel x Vd