Brainscape's Knowledge GenomeTM

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


See full index

Pharmacology RCOA > Drug metabolism > Flashcards

Drug metabolism Flashcards

1
Q

What is the best way for lipid soluble drugs to be taken?

A

Better absorbed when taken orally

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

What affects absorption?

A

Route
Lipid solubility
Gastric acidity

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

What is distribution affected by?

A

Lipid solubility: Rapidly move out of blood into fat/lipids (e.g propofol)
Protein binding: Many drugs bind to albumin and become inactive

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

What is the equation for volume of distribution?

A

Vd = total amount of drugs in body/ drug plasma conc

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

What are the phases of metabolism?

A

Phase 1: Add polar group (-OH), makes drug more reactive
Phase 2: Additional molecules added to make drug more soluble to kidneys

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

What important enzyme is used in phase 1 metabolism?

A

Cytochrome P450

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

What is a pro drug? Give an example

A

Drug given is inactive but becomes active substance when it undergoes metabolism
Codeine metabolised to morphine in phase 1 metabolism

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

Give examples of enzyme inducers

A

Phenytoin
Carbamazepine
Rifampicin
ETOH
Barbituates
Sulphonylureas

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

Give examples of enzyme inhibitors

A

Cimetidine
Amiodarone
Allopurinol
Ketoconazole
Erythromycin
Valproate

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

What is first pass metabolism?

A

Oral drugs are absorbed in the gut and all pass through the liver
If >60% is removed then drug has high 1st pass metabolism
E.g: Morphine, propranolol, Diazepam, lidocaine, nitroglycerin

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

How are drugs eliminated?

A

Hepatic - in faeces but usually in bile
Renal

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

What is First order kinetics?

A

Most drugs
However much of the drug is in the body a fixed amount is metabolised over a fixed period of time
E.g 1/2 life is the same regardless of the amount in the body

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

What is zero order kinetics?

A

Limited amount of enzyme, when that enzyme is saturated no more metabolism can happen
E.g ETOH is metabolised at 1 unit per hour if you have 3 units they will still only be metabolised at 1unit per hour
E.g ETOH, phenytoin

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

When is a steady state of a drug reached?

A

Usually 5 1/2 lives of the drug with regular dosing
E.g paracetamol 1/2 life = 2hours so steady state will be reached 2x5=10hours

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

When is a loading dose given?

A

Drugs who’s steady state time will take too long to reach
E.g Digoxin 1/2 life is 40hours so steady state would take 1 week

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

What determines the loading dose quantity?

A
  • Desired peak conc (conc)
  • Vol of distribution (Vol)
    Dose = Conc x Vol
17
Q

How do alginates work?

A

Float on top of the stomach acid so the drug is refluxed not the acid

18
Q

How do the different types of laxatives work?

A

Bulking: Fibre (Fybogel)
Stimulant: Senna, bisacodyl
Osmotic: Lactulose

19
Q

What does infliximab work on?

A

TNF

20
Q

What drugs are used to treat malaria?

A

Quinine: 1st line for Falciparum
Chloroquine: 1st line for Vivax
Malarone: Alt for Falciparum
Primaquine: Vivid/Ovale (needed to be check for G6PD levels)

21
Q

What are the SE of COX-2 inhibitors?

A

Inc thrombotic risk in COX-2 selective agents (Naproxen) = double risk of MI
General: Peptic ulcer, HF, asthma exacerbation, interstitial nephritis

22
Q

What are the SE of Thiopental?

A

Rapid recovery from small doses but prolonged in large doses
Cardioresp depression

23
Q

What are the SE of Etomidate?

A

Suppresses adrenal function- may need steroids afterwards
Avoid in sepsis
Minimal HypoT

24
Q

What are the effects of Propofol?

A

Loss of airway
Hypotension
Bradycardia
Allergic reaction
Pain on injection

25
Q

What are the effects of Ketamine?

A

Dissociative anaesthetic - higher function maintained e.g BP & airway
Bronchodilation (useful in asthma)
Inc Salivation which can cause laryngospasm
Emergence phenomena in adults

26
Q

How do induction agents act on BP?

A

Prop: Big drop
Thio: Drop
Ket: Inc
Etom: Normal

27
Q

How do induction agents act on CO?

A

Prop: Big drop
Thio: Drop
Ket: Inc
Etom: Normal/drop

28
Q

How do induction agents act on HR?

A

Prop: Drop/norm
Thio: Inc
Ket: Inc
Etom: Normal

29
Q

How do induction agents act on SVR?

A

Prop: Drop
Thio: Drop
Ket: Inc
Etom: Normal/drop

30
Q

How do induction agents act on ICP?

A

Prop: Drop
Thio: Drop
Ket: Inc
Etom: Normal

31
Q

How do neuromuscular blocking agents work?

A

Antagonises acetylcholine receptors
Non-depolarising: Atracurium.
Depolarising: Suxamethonium

32
Q

Who should Suxamethonium be avoided in?

A

Fhx of malignant hyperthermia
Hyperkalaemia
Recent major trauma/burns
Causes painful fasciculations so should be given after anaesthetic

33
Q

What are the max doses of the different LAs?

A

Lidocaine: 3mg/kg
Lidocaine w/adrenaline: 7mg/kg
Bupiv: 2mg/kg
Prilocaine: 7mg/kg

33
Q

What are the max doses of the different LAs?

A

Lidocaine: 3mg/kg
Lidocaine w/adrenaline: 7mg/kg
Bupiv: 2mg/kg
Prilocaine: 7mg/kg

34
Q
A

Pharmacology RCOA (10 decks)

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