Pharm Ch. 2 and 3: Pharmacokinetics I and II

Question 1

Alimentary Canal

Answer 1

Enteral administration

Question 2

Non-alimentary routes

Answer 2

Parenteral administration

Question 3

Oral

Answer 3

-High degree of lipid solubility to pass through GI mucosa
-Drugs enter system in controlled manner
-Final amount and rate are less predictable

Question 4

First Pass

Answer 4

Drug is transported directly to liver via portal vein and may be metabolized before it can be used/effective

Question 5

Sublingual and Buccal

Answer 5

Drugs can reach systemic circulation without being subjected to first pass. Faster than swallowing drug

Question 6

Rectal

Answer 6

-Good for when patient is unconscious or vomiting and can’t take oral drugs
-Poorly absorbed, can irritate mucosa
-Best for treating local issues

Question 7

Parenteral

Answer 7

-More direct
-More predictable quantity
-Not subject to first pass

Question 7

Inhalation

Answer 7

-Rapid entry into bloodstream through diffusion to pulmonary circulation
-Can’t predict exactly how much will reach lungs due to compliance/other things in lungs

Question 8

IV injection

Answer 8

-Frequently resulting in peak levels almost instantaneously and reach target site rapidly
-Lines allow prolonged and steady infusion

Question 9

Intra-arterial injection

Answer 9

-Difficult and dangerous
-Occasionally used in chemo

Question 10

Subcutaneous Injection

Answer 10

-Slower more prolonged release into systemic circulation
-Patients can perform on themselves

Question 11

Intramuscular Injection

Answer 11

-Easily accessible
-Steady and prolonged release
-Relatively rapid effect without rapid plasma level spikes seen with IV

Question 12

Intrathecal Injection

Answer 12

-Deliver medication in a sheath
-Bypass blood-brain barrier and reach CNS

Question 13

Topical medications

Answer 13

-Direct to skin
-Absorbed poorly thru epidermis
-Also includes mucous membranes (eyedrops, etc)

Question 14

Transdermal

Answer 14

-Absorbed thru dermal layers and into subcutaneous tissue or peripheral circulation
-Slow and controlled release, maintain constant level for prolonged period of time

Question 15

Iontophoresis

Answer 15

Drives ionized form of medication into skin (like estim)

Question 16

Phonophoresis

Answer 16

Uses ultrasound to enhance transmission of medication through dermis

Question 17

Bioavailability

Answer 17

-Extent to which drug reaches systemic circulation
-Depends on route of administration and the drug’s ability to cross membrane barriers

Question 18

Passive Diffusion

Answer 18

-Made possible through electrical, chemical, and pressure differences on either side of membrane
-Rate depends on magnitude of gradient, size, distance, and temperature

Question 19

Drugs diffuse more easily if they are in

Answer 19

Neutral, non ionized form

Question 20

Weak acid is in neutral form if

Answer 20

in acidic environment

Question 21

Weak base becomes non ionized in

Answer 21

duodenum, allows it to be absorbed into small intestine

Question 22

Drug should remain ___ in urine so it will be excreted

Answer 22

Ionized

Question 23

Active transport

Answer 23

Use membrane proteins to transport substances across cell membrane
-Carrier specificity
-Expenditure of energy
-Ability to transport substances against a gradient

Question 24

Facilitated diffusion

Answer 24

-Assisting protein carrier is present, but no energy expended -Ex: skeletal muscle glucose uptake

Question 25

Factors affecting distribution: blood flow

Answer 25

Organs with rich blood flow will make distribution easier

Question 26

Factors affecting distribution: binding to plasma proteins

Answer 26

Ex: albumin Only unbound drug can reach the target tissue and exert an effect

Question 27

Factors affecting distribution: binding to subcelluar components

Answer 27

Several drugs bound to organelles can't be distributed to other compartments

Question 28

Volume of distribution

Answer 28

Amount of drug administered/concentration of drug in plasma

Question 29

Drug storage: adipose tissue

Answer 29

Primary site since most drugs are lipid soluble

Question 30

Drug storage: bone

Answer 30

Toxic agents and heavy metals

Question 31

Drug storage: muscle

Answer 31

May lead to long term storage

Question 32

Drug storage: organs

Answer 32

Ex: liver and kidneys Enters passively or actively and forms bonds to subcellular components

Question 33

Adverse consequences of drug storage

Answer 33

-High concentrations can cause local damage -Reservoir "soaks up" a drug and prevents it from reaching target site -Can leak out and reintroduce drug long after dose should have been eliminated

Question 34

Biotransformation

Answer 34

Chemically altering a compound usually in liver so it is no longer active. Fast (minutes/hours)

Question 35

Excretion

Answer 35

Active form is excreted, slow and not very effective (good for removing byproducts of biotransformation)

Question 36

Phase 1 Reactions

Answer 36

Oxidation, reduction, hydrolysis. Conjugation happens afterwards

Question 37

Phase 2 Reactions

Answer 37

Conjugation

Question 38

Oxidation

Answer 38

Oxygen added or hydrogen removed

Question 39

Reduction

Answer 39

Oxygen removed or hydrogen added

Question 40

Hydrolysis

Answer 40

Original compound broken into 2 parts

Question 41

Conjugation

Answer 41

Intact drug or metabolite from one of earlier actions is coupled to endogenous substance

Question 42

Enzyme Induction

Answer 42

-Prolonged use of certain drugs induces body to adjust and destroy drug more rapidly than expected -More enzymes being manufactured or less degraded -Can lead to tolerance

Question 43

Excretion in Kidneys

Answer 43

-Traps ionized water soluble compounds for elimination via urine -Can be reabsorbed back via passive diffusion

Question 44

Clearance

Answer 44

Organ/tissue ability to eliminate drug -Depends on ability to extract drug and flow of blood (Q)

Question 45

Half-Life

Answer 45

-Amount of time it takes for 50% of drug remaining to be eliminated -Function of both clearance and volume of distribution

Question 46

Dosing Schedules

Answer 46

Larger doses given further apart result in greater plasma fluctuations