Drug disposition and fate of drugs

Question 1

General Principles of Drug Absorption (Routes of Administration)

Answer 1

1. Drug dissolve in body fluid (water).
2. Drugs enter the circulatory system as fluid enters the circulatory system.
3. Drugs must enter the circulatory system before they can distributed to sites of
   action.
4. Therefore, drugs are not IN the body until they are IN the bloodstream.

Question 2

It is convenient, cheap, no need for sterilization, variety of dose forms

Answer 2

Oral administration

Question 3

Disadvantages of Oral administration

Answer 3

1. Variability due to physiology, feeding, disease, etc.
2. Intractable patients
3. First-pass effect
4. Efficiently metabolized drugs eliminated by the liver before they reach the
   systematic circulation.

Question 4

It can be given by the owner (small patients); vasoconstrictor can be added to prolong effect at site of interest

Answer 4

subcutaneous administration

Question 5

When applied, patients groom themselves

Answer 5

topical

Question 6

Patient and pharmaceutical factors of oral admin.

Answer 6

1. Pill compression, coatings, suspending agents, etc.
2. GI transit time (too slow or too fast), inflammation, malabsorption, syndromes

Question 7

patient and pharmaceutical factors of SC administration

Answer 7

1. More autonomic control over blood flow (than muscle)
2. dehydration, heat, cold, stress

Question 8

its patient and pharmaceutical factors include lipid solubility and molecule size, skin hydration and abrasion, area of application, ambient an patient temperature

Answer 8

topical

Question 9

Larger absorptive surface are than IM / Subcutaneous

Answer 9

intraperitoneal

Question 10

may cause peritonitis and damage to organs by needles

Answer 10

intraperitoneal

Question 11

Generally restricted to laboratory animals

Answer 11

intraperitoneal

Question 12

route of administration for drugs via an injection into the spinal canal, or into the subarachnoid space so that it reaches the cerebrospinal fluid (CSF)

Answer 12

Intrathecal

Question 13

administered in the joint

Answer 13

intra-articular

Question 14

Produce extremely high concentrations “pointed at” the tissue of interest.

Answer 14

intra-arterial

Question 15

Used primarily for anti-tumor therapy and infectious disease therapy when blood supply is questionable

Answer 15

intra-arterial

Question 16

Access to GI absorption in unconscious or vomiting patients

Answer 16

per rectum

Question 17

any chemical substance which modify the functions of a biological
system and primarily intended for the treatment, prevention or diagnosis of
disease to man or animals

Answer 17

drug

Question 18

the pharmacopeia of the United States of America (1820)

Answer 18

USP

Question 19

British Pharmacopeia

Answer 19

B.P

Question 20

B.P.C

Answer 20

the British Pharmaceutical Codex (1907

Question 21

N.F.

Answer 21

national formulary

Question 22

study the actions of drugs on living things

Answer 22

pharmacology

Question 23

C.F

Answer 23

canadian formulary

Question 24

Ph. I.

Answer 24

International Pharmacopeia

Question 25

C.F.

Answer 25

codex francis

Question 26

drug mixtures prepared from crude drugs and containing several organic ingredients

Answer 26

galencials

Question 27

a blank preparation containing only innocuous ingredients

Answer 27

placebo

Question 28

extent to which the active ingredient in a drug product can be taken up by the body in a form which is physiologically active in order to exert the desired therapeutic effect

Answer 28

bioavailability

Question 29

in order to be absorbed, reach sites of action drugs must have the ability dissolve in?

Answer 29

water

Question 30

drugs can leave and enter capillaries, and enter and leave cells, through?

Answer 30

lipid solubility

Question 31

measured in either serum or plasma

Answer 31

drug concentration in blood stream

Question 32

easy painless application of topical drug

Answer 32

systemic therapy

Question 33

reduced systemic effects/enhanced skin effects of topical drug

Answer 33

skin therapy

Question 34

disadvantages of topical

Answer 34

1. Patients groom themselves (topically applied, orally absorbed) 2. Toxic skin reactions 3. Variable blood flow to skin 4. Complex relationship between drug, vehicle , skin physiology

Question 35

Diffusion through stratified epithelium “Passage” through adnexal structures

Answer 35

topical administration

Question 36

True or false. “like” vehicles retain drug on skin surface while drugs in “unlike” vehicles leave the vehicle to move on to skin

Answer 36

true

Question 37

Its disadvantages are: 1. Difficult dose calculation 2. CSF volume is not proportional to body weight 3. Toxicity likely, and toxicity may be unusual 4. Introduce infection into a VERY bad location

Answer 37

Intrathecal

Question 38

One of the disadvantages are limited number of efficacy studies (especially in animals)

Answer 38

intra-arterial

Question 39

Animals may not willingly retain the drug

Answer 39

per rectum

Question 40

Its process is like oral without mechanical preparation by stomach

Answer 40

per rectum

Question 41

7% of body weight

Answer 41

Vascular space

Question 42

Extracellular Space size

Answer 42

15 - 20% of bw

Question 43

distribution of drug in vascular space

Answer 43

10 - 30 minutes

Question 44

Extracellular Space distribution

Answer 44

30 minutes - 1.5 hours

Question 45

intracellular space size

Answer 45

35 – 45% of body weight

Question 46

distribution in intracellular space

Answer 46

30 minutes to 12+hours

Question 47

Give three reserved spaces.

Answer 47

1. Special barriers between plasma and tissue fluid CSF 2. aqueous humor 3. prostatic fluid

Question 48

Distribution in minutes to never

Answer 48

reserved spaces

Question 49

three processes in renal excretion

Answer 49

1. Glomerular filtration 2. tubular secretion 3. passive reabsorption

Question 50

renal elimination of aspirin can go from _____ of total elimination

Answer 50

2% to 30%

Question 51

volume of fluid that “appears” to contain the amount of drug in the body

Answer 51

volume of distribution

Question 52

volume of plasma water cleared of the drug during a specified time period

Answer 52

clearance

Question 53

sum of all organ clearances

Answer 53

Total body clearance (Clt)

Question 54

fraction of the volume of distribution cleared per unit time

Answer 54

rate constant elimination

Question 55

time for elimination of one half of the total amount in the body

Answer 55

elimination half-life

Question 56

initial dose of drug given to shorten the time to reach the steady-state concentrations

Answer 56

loading dose

Question 57

describes the rate of drug movement (oral, IM, SC, etc.) from the dose to the circulatory system

Answer 57

absorption rate constant

Question 58

Two drug products are ______ if the nature and extent of therapeutic and toxic effects are equal following administration

Answer 58

bioequivalent

Question 59

Attempt to describe the actual events which control drug absorption, distribution, and elimination

Answer 59

physiologic model/pharmacokinetics model

Question 60

absorption rate decrease as the dose increases

Answer 60

dose-dependent absorption

Question 61

clearance and the elimination rate constant decrease as the dose increases

Answer 61

dose-dependent elimination

Question 62

The sum of all individual organ clearances. Usually determined by plasma sampling

Answer 62

total clearance (CLT)

Question 63

The clearance “performed” by the kidney.

Answer 63

renal clearance (CLR)

Question 64

The clearance “performed’ by the liver.

Answer 64

hepatic clearance (CLH)

Question 65

highest plasma concentration achieved following a single non-intravenous dose of a drug.

Answer 65

peak plasma concentration (cmax)

Question 66

portion of a non-intravenous dose of drug that reaches the systemic circulation.

Answer 66

fraction of dose absorbed

Question 67

Time required to eliminate 50% of any amount of drug from the body

Answer 67

half life elimination