Block E Lecture 1: Pharmacokinetics

Question 1

What is pharmacokinetics?

Answer 1

A drug’s journey through the body, which is broken down into 4 steps
(Slide 6)

Question 2

What are the 4 steps of pharmacokinetics?

Answer 2

Absorption
Distribution
Metabolism
Excretion
(Remember ADME)
(Slide 6)

Question 3

What does the absorption stage of pharmacokinetics observe?

Answer 3

Observing how a drug travels from the site of administration to the site of action
(Slide 6)

Question 4

What does the distribution stage of pharmacokinetics observe?

Answer 4

Observes the passage of a drug through the bloodstream to different tissues in the body
(Slide 6)

Question 5

What does the metabolism stage of pharmacokinetics observe?

Answer 5

The activity which breaks down a drug
(Slide 6)

Question 6

What does the excretion stage of pharmacokinetics observe?

Answer 6

The elimination of a drug from the body
(Slide 6)

Question 7

Why are blood / plasma drug concentrations measured in pharmacokinetics?

Answer 7

As they are easy to access
(Slide 9)

Question 8

What is assumed when measuring drug blood / plasma concentrations in pharmacokinetics?

Answer 8

An equilibrium with plasma concentration and receptor concentration
(Slide 9)

Question 9

How is a pharmacological response measured on a graph?

Answer 9

A log concentration response curve (Log of the dose on the x axis with effect measured on the Y)
(Slide 11)

Question 10

How is potency taken from a log concentration response curve?

Answer 10

By looking at the EC50 value (A lower concentration value = more potent)
(Slide 11)

Question 11

How can efficacy be taken from a log concentration response curve?

Answer 11

By looking at the dose concentration at which the drug performs it’s maximal effect (lower concentration = more efficacy)
(Slide 11)

Question 12

What is the therapeutic window?

Answer 12

The drug dosage range which is enough to produce the desired response while reducing the risk of adverse effects
(Slide 13)

Question 13

What is TD50?

Answer 13

The median toxic dose of a substance at which toxicity occurs in 50% of the cases
(Slide 13)

Question 14

What are 3 different scales which a drug’s site of action can be defined by?

Answer 14

Anatomical - The compartment of the body the drug has to reach (e.g tissues)
Cellular - The type of cell the drug has to reach
Molecular - The molecular target which the drug needs to bind to (e.g cell surface receptor)
(Slide 14)

Question 15

What are direct oral anticoagulants?

Answer 15

DOACs are small molecules which occupy the catalytic site of Fxa or thrombin, preventing their capacity to cleave and activate their substrates
(Slide 15)

Question 16

What compartment is the site of action of direct oral anticoagulants (DOACs)?

Answer 16

The central plasma compartment
(Slide 15)

Question 17

What receptors are caffeine’s site of action?

Answer 17

Adenosine receptors
(Slide 15)

Question 18

Where are A2A, A2B and A3 receptors (which are caffeine’s site of action) found in the body?

Answer 18

A2A is mainly found in the brain, heart, lungs and spleen
A2B is found in the large intestine and bladder
A3 is present in the lungs, liver, brain testis and hearts
(Slide 15)

Question 19

What is the site of action of temozolomide?

Answer 19

DNA of brain tumour cells
(Slide 15)