Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PED1003-Pharmacology > PED1003/L06 Drug Elimination II > Flashcards

PED1003/L06 Drug Elimination II Flashcards

1
Q

Give the 3 major systems of elimination in the body.

A

Kidneys
Hepato-biliary system
Lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which group of enzymes is a key player in Phase I reactions?

A

Cytochrome P450s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which kind of drug are Phase I reactions particularly important for?

A

Pro-drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe a basic CYP reaction. (5)

A

Drug enters cycle
Forms complex with CYP450
Through series of e- donations with NADPH as cofactor
Produces a metabolite
CYP regenerated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give an exception to the CYP cycle.

A

Ethanol metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the most common conjugation reaction?

A

Glucuronidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is glucuronidation mediated?

A

By UDP-glucuronyl transferases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why are glucuronides usually pharmacologically inactive and rapidly excreted?

A

They are polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is NAPQI?

A

Toxic metabolite of paracetamol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens in paracetamol overdose? (2)

A

Tissues become saturated with glutathione
Reacts and damages liver proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Give 3 internal factors that affect how an individual responds to a drug.

A

Genetics
Age
Disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Give 3 external factors which affect how an individual responds to a drug.

A

Drugs
Alcohol
Environmental exposure including diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give 4 features of fast metabolisers.

A

Normal enzyme activity
Lower plasma conc.
Higher metabolite conc.
Generally normal therapeutic response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give 4 features of slow metabolisers.

A

Low enzyme activity
Higher plasma conc.
Lower metabolite conc.
May lead to exaggerated therapeutic response at normal doses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe induction of drug metabolising enzymes. (2)

A

Increased synthesis of enzymes
Increased metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give 3 implications of induction.

A

Decreased drug effectiveness
Need to increase drug dose
In MDT may be problems when inducer is withdrawn from specimen
Basis of many drug-drug interactions

17
Q

Give a drug which is rapidly and slowly cleared from blood.

A

Rapid - penicillin
Slow - diazepam

18
Q

Give the 3 major processes of the kidney.

A

Glomerular filtration
Tubular reabsorption
Tubular secretion

19
Q

Describe glomerular filtration.

A

Molecules of certain size pass from blood into nephron to be excreted (in glomerulus)

20
Q

Describe tubular reabsorption.

A

In PCT
Acidic/basic molecules transferred from blood into nephron to be excreted

21
Q

Describe tubular secretion.

A

Water is reabsorbed into body

22
Q

Describe the path of a lipid soluble drug in the kidney. (4)

A

Filtered in glomeruli
Reabsorbed on distal portion of nephron
Metabolism to more polar compounds
Excretion in urine

23
Q

Which plasma binding protein is almost completely retained?

A

Albumin

24
Q

What does the rate of entry in glomerular filtration depend on? (2)

A

Concentration of free drug in plasma
Molecular weight

25
Q

Which two carrier systems transport against an electrochemical gradient during tubular secretion?

A

For acids
For bases

26
Q

More water-soluble drugs have what features during tubular reabsorption? (2)

A

Low tubular permeability
Concentrate in urine (100x that in plasma)

27
Q

What si the extent of absorption dependent on?

A

Drug lipid solubility
pH of tubular fluid

28
Q

What happens as fluid becomes more alkaline during tubular absorption? (3)

A

Acid drugs ionise
Become less lipid soluble
Reabsorption diminishes
(Basic drug un-ionised = reabsorption increases)

29
Q

At what pKa is half of a substance ionised?

A

0

30
Q

What is pH partitioning?

A

Acidic drugs accumulate in basic fluid compartments and vice versa

31
Q

What is saturable elimination?

A

Elimination mechanisms are typically not saturated at therapeutic doses of drugs, with few exceptions

32
Q

What is the purpose of Phase II reactions?

A

Increase water solubility to improve excretion

PED1003-Pharmacology (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions