PharmacoKinetics And Dynamics

Question 1

Pharmacokinetics

Answer 1

Study of the drug actions on the body. How drugs are transported into and out of the body

Question 2

To have its desired effect, what must a drug do?

Answer 2

Reach its target, be of sufficient concentration

Question 3

What are the 4 factors that influence drug concentration?

Answer 3

Absorption, distribution, bio transformation, elimination

Question 4

Absorption

Answer 4

The movement of a drug from the site of application to the specific target

Question 5

Distribution

Answer 5

The process whereby a drug is transported from the site of absorption to the site of action

Question 6

Biotransformation

Answer 6

How a drug is metabolized or broken down into different chemicals

Question 7

Elimination

Answer 7

Movement of a drug out of the body

Question 8

Factors that affect the rate of drug absorption

Answer 8

Drug solubility, drug concentration, drug pH, site of absorption, absorbing surface area, circulatory status, bioavailability

Question 9

Drug solubility

Answer 9

Tendency of a drug to dissolve, “like dissolves like”, drugs given in water based solutions are more quickly dissolved than those in oil-based solutions. It may sometimes be beneficial to have slower or faster absorption

Question 10

Drug concentration

Answer 10

Drugs given in high concentration are more quickly absorbed than those in low concentration, drugs administered by more than one route may have various concentrations

Question 11

Drug pH

Answer 11

Acidic vs alkaline (basic), acidic drugs more readily absorbed in acidic environments (stomach), basic drugs more rapidly absorbed in alkaline environments (kidneys)

Question 12

Site of absorption

Answer 12

Affects rate of absorption (subcutaneous, intravenous), drugs have to pass through various membranes prior to entering the general circulation

Question 13

Absorbing surface area

Answer 13

Drugs are absorbed more quickly if the surface area is larger. Drugs given by inhalation or down the endotracheal tube absorbed rapidly due to large pulmonary surface area

Question 14

Blood supply to the site of absorption

Answer 14

Different body tissues and organs have varied degrees of blood supply. Pulmonary, epithelium, sublingual tissues have rapid absorption.

Question 15

What will affect systemic blood flow?

Answer 15

Hypothermia, shock, dehydration

Question 16

Bioavailability

Answer 16

The amount of drug that is still active after it reaches its target tissue, there must be sufficient amount of the drug still available to produce the desired effect

Question 17

What are the 4 factors of distribution?

Answer 17

Cardiovascular function, regional blood flow, drug storage reservoirs, physiological barriers

Question 18

Normal Cardiovascular function

Answer 18

Drugs are distributed first to highly perfused areas (brain, heart, liver, lungs). Drugs are delivered secondly to less perfused areas (GI system, muscles, skin then fat)

Question 19

What does impaired cardiovascular function result in?

Answer 19

Slower unpredictable drug distribution, with decreased perfusion, there is decreased drug delivery

Question 20

What would cause impair distribution in cardiovascular function?

Answer 20

Heart disease (CHF)

Question 21

How does regional and systemic blood flow impact drug distribution?

Answer 21

Cardio genie shock states could impede circulation of diuretics to kidneys, drugs intended to reduce cerebral edge a may not reach all parts of the brain if cerebral circulation is already significantly compromised

Question 22

What circulating proteins do drugs bind to, to travel through the body?

Answer 22

Hemoglobin, albumin, globulin

Question 23

Distribution

Answer 23

Onset of action

Question 24

Bound drug

Answer 24

If the drug binds with the receptor protein or becomes stored in the body’s fatty tissues

Question 25

Free drug

Answer 25

The unbound; available to target tissues

Question 26

What is the most common circulation protein?

Answer 26

Albumin

Question 27

Physiological barriers

Answer 27

Considered a protective mechanism

Question 28

What are the two main physiological barriers?

Answer 28

Blood-brain barrier, placenta barrier

Question 29

Blood-brain barriers

Answer 29

Tightly packed cell membranes restrict damaging drugs and toxins; only non protein bound, highly lipid soluble drugs can cross these barriers

Question 30

What does the blood-brain barrier consist of?

Answer 30

Network of capillary endothelial cells (no pores), surrounded by glial connective tissues, impermeable to water-solvable drugs

Question 31

What’s is the blood-brain barrier ineffective against?

Answer 31

Fats, fatty acids, oxygen, CO2, fat soluble molecule, anaesthetics, nicotine, entonox, alcohol

Question 32

Placental barrier

Answer 32

Placenta acts as a barrier to some substances passing from mother into fetal circulation; to cross the barrier drug must be: lipid soluble, non-protein bound

Question 33

What is biotransformation dependent on?

Answer 33

Chemical composition, protein capacity, metabolizing system function

Question 34

Where does biotransformation occur?

Answer 34

Usually occurs in the liver (hepatic biotransformation), can occur in the kidneys, liver, GI Tract

Question 35

Hepatic “first pass” metabolism

Answer 35

Affects orally administered drugs GI tract blood supply passes through the liver May reduce avaliablility of drug IV meds bypass this system

Question 36

Decreased biotransformation

Answer 36

Cumulative drug effects may occur

Question 37

Increased biotransformation

Answer 37

This effect results in the need for some drug addicts and alcoholics to gradually increase their “dose” as the body becomes more efficient at metabolizing the drug

Question 38

Biotransformation inhibition

Answer 38

Alternately some drug can inhibit the metabolism of other drugs (acetaminophen and alcohol)

Question 39

Elimination

Answer 39

Movement not a drug out of the body

Question 40

What can elimination be affected by?

Answer 40

Accumulation of drug in the body, a drugs half life

Question 41

Drug half-life

Answer 41

Time required for the total amount of a drug in the body to diminish by half

Question 42

Pharmacodynamics

Answer 42

What the drug will do to the body, drug and receptors bind to initiate a response

Question 43

Predictable responses

Answer 43

Anticipate responses beyond the desired effect

Question 44

Factors affecting drug response

Answer 44

Age, weight, gender, environment, time of administration, condition of the patient, genetic factors

Question 45

Drug activity; therapeutic index

Answer 45

Minimum drug amount, excess drug, dosage

Question 46

Iatrogenic responses

Answer 46

An adverse condition inadvertently induced in a patient by the treatment given; most common - allergy to drug, infection from procedure

Question 47

Unpredictable responses

Answer 47

Tolerance, minimum concentration, drug dependency

Question 48

Tolerance

Answer 48

Decreased response to the same amount of medication

Question 49

Minimum concentration

Answer 49

Concentration needed to become effective

Question 50

Drug dependency

Answer 50

Prolonged administration may lead to this. Significant symptoms if stop using the medication

Question 51

What are the 4 effects of multiple medications?

Answer 51

Cumulative effect, summation effect, synergism, potentiation

Question 52

Cumulative effect

Answer 52

Increase effort of a drug given in several successive doses

Question 53

Summation effect

Answer 53

2 drugs, doubles the response

Question 54

Synergism

Answer 54

2 drugs, response greater than the sum of their individual responses

Question 55

Potentiation

Answer 55

2 drugs that causes the effects of one drug to be enhanced