Pharmacokinetics

Question 1

Determines the rate of absorption

Answer 1

Time - plasma drug concentration relationship

Question 2

What is “First order kinetics”
Example; half - life

Answer 2

• Constant percentage, each time, is absorbed/disappeared from the site of administration
• The rate of change of drug concentration is directly proportional to the concentration of the drug at the time. (merck)

Question 3

What is “zero order kinetics”
Example; drugs do not have true half - life

Answer 3

• Fixed rate of drug absorption and elimination
• Constant amount of drug absorbed per unit of time

Question 4

Drugs do not have true half - life

Ex. Ethanol is eliminated at 10 ml/hr regardless of how much you drink

Answer 4

P - phenytoin
P - phenylbutazone
E - ethanol
A - aspirin
D - dicumarol

Question 5

Measures the drug concentration from the 1st absorption to the last. It determines bioavailability

Answer 5

Area under the curve (AUC)

Question 6

(True or False). Drugs with high Vd have much higher concentrations in extravascular tissue?

Answer 6

True

Question 7

The time it takes for a drug concentration to be reduced to half of its initial concentration?

Answer 7

Half - time (t 1/2)

Question 8

Half - time includes the process of?

Answer 8

B - biotransformation
E - elimination
D - distribution

In order (D. B. E.)

Question 9

The rate of drug elimination is directly proportional to concentration. Follows the 1st order kinetic process.
It is also the single most important factor determining drug concentrations

Answer 9

Total Body Clearance

Question 10

The fraction of unchanged drug reaching the systemic circulation following administration by any route

Answer 10

Bioavailability

Question 11

Drugs are exposed to low pH ranges, digestive enzymes, enteric microflora and ingesta that vary greatly between species

Answer 11

Oral route ( by mouth; per os; per orem, p.o.)

Question 12

Aqueous solution is preferable, which leads immediately high blood levels with rapid onset of action

Answer 12

Intravenous route

Question 13

In the subcutaneous route, absorption can be enhanced by increasing the blood supply to the area thoroughly?

Answer 13

Warmth or vigorous massage or
Inclusion of the enzyme “hyaluronidase” in the formulation

Question 14

Enumerate sites of absorption

Answer 14

G - gastro - intestinal
R - respiratory tract
I - intraperitoneal
P - parenteral
S- skin

Question 15

Factors affecting gastro - intestinal absorption

Answer 15

• Lipid solubility of drugs
• Degree of ionization (Drugs must be less ionized)
• Nonionized

Question 16

Factors affecting parenteral route absorption

Answer 16

V - vascularity of the site
V - volume of injection
O - osmolality of the solution
C - concentration and lipid solubility of the drug

Question 17

How to increase the rate of absorption in the parenteral route?

Answer 17

• heating, massage, or exercise
• add hyaluronidase in large volume in SC

Question 18

How to decrease the rate of absorption in the parenteral route?

Answer 18

• immobilization of the site, local cooling, a tourniquet
• incorporation of vasoconstrictor, an oil base, implant pellets, insoluble “depot” preparation

Question 19

How to reduce the chances of inducing drug reactions in the intravenous route

Answer 19

Allow at least one circulation time (1-2 minutes) to complete an intravenous injection

Question 20

Absorption from this route is usually complete but drugs may undergo first pass effect, as they are also absorbed into the hepatic portal circulation from the peritoneal cavity

Answer 20

Intraperitoneal absorption

Question 21

Most important in xenobiotics

Answer 21

Passive diffusion

Question 22

P - glycoprotein

Answer 22

Facilitate transport

Question 23

Intestinal epithelial cells and renal tubular cells

Answer 23

Pinocytosis

Question 24

The anesthetic effect of thiopental is terminated by:
A. Biotransformation
B. Redistribution
C. Excretion
D. Distribution

Answer 24

B. Redistribution

Question 25

Drugs exhibiting the redistribution phenomenon are

Answer 25

Highly lipid - soluble