Pharmacokinetics and pharmacodynamics

Question 1

Give a definition of pharmacodynamics

Answer 1

the study of a drug’s molecular, biochemical, and physiologic effects or actions

Question 2

What does drug absorption usually involve?

Answer 2

Diffusion of drugs
Carriers and channels
Pinocytosis (for large molecules)

Question 3

Which mechanism transports insulin across the blood/brain barrier?

Answer 3

Pinocytosis

Question 4

What determines how long a drug is in the body?

Answer 4

Diffusion of the drug through lipids. The larger the molecule, the longer it takes to move through the lipid membrane

Question 5

What is the diffusion coefficient equation?

Answer 5

1/sqrt (molecular weight)

Question 6

What 5 factors affect drug absorption?

Answer 6

Method of administration
Molecular weight
Lipid solubility
pH and ionisation
Carrier transport

Question 7

What is the quickest drug administration route?

Answer 7

Intravenous

Question 8

Which drug administration route is done for rapid access to the CNS?

Answer 8

Intrathecal (puncture into the spinal fluid)

Question 9

Which drug administration route is through the skin

Answer 9

Percutaneous, e.g nicotine patches

Question 10

Which drug administration route avoids first pass metabolism?

Answer 10

Sublingual

Question 11

How are drugs distributed around the body?

Answer 11

Cardiovascular system
Non-polar molecules dissolving freely in lipids

Question 12

How does increasing blood pH affect weak acids in the body?

Answer 12

Increases excretion through urine.
Weak acids move from the CNS to plasma

Question 13

When tight junctions lining the blood brain barrier become leaky, how can the damage be treated?

Answer 13

IV penicillin

Question 14

Albumin is highly charged so mainly distributes what sorts of drug?

Answer 14

Acidic drugs.

Question 15

How is volume of distribution calculated?

Answer 15

Dose/Cp
High Vd means the drug makes its way into lots of compartments

Question 16

What part of renal excretion are weak acids and bases excreted?

Answer 16

Active tubular secretion

Question 17

What do phase 1 catabolic reacitons do?

Answer 17

Produce a more reactive compound

Question 18

What do phase 2 synthetic reactions do?

Answer 18

Produce an inactive compound

Question 19

What sort of graph does a drug time course give?

Answer 19

mono-exponential decay, determined by metabolism and excretion

Question 20

Give a definition of pharmacokinetics

Answer 20

the study of drug absorption, distribution, metabolism, and excretion

Question 21

What are genetic variants of organic cation transporter (OCT1) associated with?

Answer 21

Different metformin responses in healthy humans

Question 22

What can drug occupancy at equilibrium be used to determine?

Answer 22

Affinity

Question 23

How is drug occupancy measured?

Answer 23

Radioligand binding curves

Question 24

Give some advantages and disadvantages of using 3H as a radioligand marker

Answer 24

Labelled product
indistinguishable from native compound
Good stability
12.5 year half life
Expensive
Difficult labelling

Question 25

Give some advantages and disadvantages of using 125I as a radioligand marker

Answer 25

Can be incorporated at high specific activities if there is an aromatic hydroxyl group
Readily degraded
Short half life

Question 26

How should radioligands so that they stay biologically active?

Answer 26

Pure
Labelling must have high specific activity
Store in free-radical scavenger
stored at low temperature
avoid light
Store with antioxidants

Question 27

Why did sulfathiazole kill 300 people?

Answer 27

Had sedative phenobarbital
Multiple control deficiencies in the plant

Question 28

Why did thalidomide cause severe birth defects?

Answer 28

The stereoisomer of the drug caused these

Question 29

What does general toxicology address?

Answer 29

Clinical pathology (find which organs are affected)
Haematology
Kidney and liver function
Coagulation

Question 30

How is dose selection for humans usually found?

Answer 30

Doses being refined on animals