Pharmacology

Question 1

Define pharmacokinetics

Answer 1

Science of the rate of movement of drugs within biological systems, affected by the absorption, distribution, metabolism and elimination of medications

Question 2

Define pharmacodynamics

Answer 2

the study of the biochemical and physiologic process underlying drug action including mechanism of drug action, drug receptor interaction, efficacy and safety profile

Question 3

What is bioavailability?

Answer 3

the fraction of the administered dose of the drug which reaches the systemic circulation

Question 4

What factors affect bioavailability?

Answer 4

Molecular weight / ionisation
absorption
absorption (gastric pH, health of GI tract)
first pass metabolism

Question 5

What is the apparent volume of distribution?

Answer 5

Total amount of drug in the body divided by the drug blood plasma concentration

Question 6

What is clearance?

Answer 6

The volume of plasma cleared of drug per unit time

Question 7

What is half-life?

Answer 7

Time required for serum plasma concentration to decrease by half

Question 8

How many half lives does it take for a drug to reach a steady state or to be completely cleared?

Answer 8

4-5 times

Question 9

In non-linear pharmacokinetics dosage increases can saturate binding sites and result in non-proportional increases in drug levels. T/F?

Answer 9

True

Question 10

Loading doses are used for drugs with a short half-life. T/F?

Answer 10

False - used for drugs with a long half-life

Question 11

How is morphine prescribing altered when changing from an oral to sub cut dose?

Answer 11

Prescribe 1/3 of the oral dose

Question 12

At what dose is phenytoin prescribed?

Answer 12

15mg/kg

Question 13

Renal function affects the loading dose. T/F?

Answer 13

False

Question 14

Renal function affects maintenance dose. T/F?

Answer 14

True - it depends on drug clearance

Question 15

Name the different types of drug receptors.

Answer 15

Regulatory proteins
enzymes
transport molecules
structural proteins

Question 16

What is affinity?

Answer 16

A measure of the propensity of a drug to bind to a receptor

Question 17

What is efficacy?

Answer 17

The ability of a bound drug to change the receptor in a way which produces an effect

Question 18

Potency is clinically relevant. T/F?

Answer 18

False

Question 19

Agonists have affinity and efficacy. What about antagonists?

Answer 19

Antagonists have affinity but not efficacy

Question 20

How can the actions of competitive antagonists be reversed?

Answer 20

By increasing agonist concentration

Question 21

How is therapeutic index calculated?

Answer 21

TI = TD50 or LD50 / ED50

Question 22

Drugs acting on the same receptor or enzyme system often have the same TI. T/F?

Answer 22

True

Question 23

GFR declines with age. T/F?

Answer 23

True

Question 24

Give examples of drugs which have increased effects in older people.

Answer 24

Fentanyl, diazepam, alcohol, morphine, theophylline

Question 25

Give examples of drugs which have a diminished effect in older people.

Answer 25

Isoproterenol | beta blockers

Question 26

Polypharmacy is a risk for drug-drug interactions and adverse drug reactions. T/F?

Answer 26

True

Question 27

Give common examples of drug-drug reactions.

Answer 27

Statins and erythromycin/other antibiotics verapamil and beta blockers warfarin and aspirin ACE inhibitors and sulphonylureas

Question 28

What is the side effect of using decongestants or anticholinergics in benign prostatic hyperplasia?

Answer 28

Urinary retention

Question 29

What drugs can worsen constipation?

Answer 29

Calcium Anticholinergics Calcium channel blockers

Question 30

Give examples of drugs which lower seizure thresholds.

Answer 30

neuroleptics | quinolone

Question 31

Give an example of a drug which can exacerbate chronic heart disease.

Answer 31

NSAIDs

Question 32

How does renal disease affect pharmacokinetics and pharmacodynamics?

Answer 32

Decreased elimination, protein binding and hepatic metabolism alters sensitivity to drug effects increased adverse events

Question 33

Give examples of drugs which should be avoided in renal disease.

Answer 33

Metformin | NSAIDs

Question 34

Give examples of drugs whose dose should be reduced in renal disease

Answer 34

Antibiotics digoxin phenytoin

Question 35

How does hepatic impairment affect pharmacokinetics and pharmacodynamics

Answer 35

First pass metabolism activation of prodrugs decreased protein binding decreased elimination

Question 36

Give examples of drugs which increase bioavailability

Answer 36

chlormethiazole verapamil paracetamol

Question 37

Give examples of drugs which decrease bioavailability

Answer 37

enalapril | perindopril

Question 38

How is dosing interval affected by renal disease?

Answer 38

Require increased dosing interval

Question 39

How is dosing interval affected by hepatic disease?

Answer 39

Require increased dosing interval

Question 40

How is dosing interval affected by cystic fibrosis?

Answer 40

Decreased dosing interval