Pharmacology Flashcards Preview

2MB Dermatology > Pharmacology > Flashcards

Flashcards in Pharmacology Deck (49)
Loading flashcards...
1

Immunologically-mediated skin reactions are dose-dependent. True/False?

False
All or nothing!

2

Non-immunologically-mediated skin reactions can be dose-dependent. True/False?

True

3

How do urticarial drug eruptions usually arise?

IgE-mediated hypersensitivity or drug-induced mast cell degranulation

4

Which drugs tend to cause pustular/bullous drug reactions?

Glucocorticoids
Androgens
Hypertensives

5

Fixed drug eruptions are well-demarcated and round. Which drugs are commonly associated with this?

Tetracycline antibiotics
Paracetamol
NSAIDs
Carbamazepine (anti-epileptic)

6

What are the 3 major routes of drug administration through the skin?

Topical
Transdermal
Subcutaenous

7

What is the single most important barrier to drug administration?

Stratum corneum (made up of corneocytes)

8

The stratum corneum is made up similar to a "bricks and mortar" model. What are the bricks?

Corneocytes embedded in filaggrin that are held together by corneodesmosomes

9

The stratum corneum is made up similar to a "bricks and mortar" model. What is the mortar?

Hydrophobic layer made up of intercellular lipids

10

Is the stratum corneum hydrophilic or lipophilic?

Lipophilic
Absorbs lipid-soluble (hydrophobic drugs)

11

The principle mechansim of drug penetration of the stratum corneum is transcellular (across the stratum corneum). True/False?

False
Principle mechanism is intercellular (tortuous course between corneocytes)

12

Drug vehicles are normally used in topical administration of drug (for local effect). What are vehicles?

Pharmacologically inactive substances that "carry" the drug

13

List some examples of drug vehicles

Ointments
Creams
Gels
Lotions
Pastes and powders

14

Rate of absorption of a topically administered drug = ?

J = Kp x Cv
Kp = permeability coefficient
Cv = concn of drug in vehicle

15

A drug must exit its vehicle if it is to penetrate the stratum corneum. True/False?

True

16

The bigger the Km of a drug, the better it will enter the skin. True//False?

True

17

Lipophilic drug in a hydrophilic vehicle absorb poorly in skin. True/False?

False
They absorb very well

18

Lipophilic drug in a lipophilic vehicle absorb very well in skin. True/False?

False
While they will absorb, the drug will want to remain in the lipophilic vehicle at the same time, so absorption is not great

19

Hydrophilic drug in a lipophilic vehicle don't absorb very well. Why?

They will make it out of the vehicle but cannot penetrate the stratum corneum because they are hydrophilic

20

Hydrophilic drug in a hydrophilic vehicle absorb the best of all. True/False?

False
They ain't going nowhere

21

What can enhance the absorption of a drug in skin?

Excipients

22

What are creams?

Semi-solid emulsion of oil and water containing emulsifier and preservative

23

Creams are cooling and greasy. True/False?

False
They are cooling but not greasy

24

What is the danger of the preservative in creams?

Allergic reaction

25

What are ointments?

Semi-solid mix of grease and oil containing soft paraffin

26

What is the benefit of ointments?

Effective at restricting transepidermal water loss

27

What is the downside of ointments?

Not cosmetically attractive (very greasy)

28

What are lotions?

Suspension of medication in water/alcohol/other liquid

29

What are gels?

Thickened aqueous solutions containing high molecular weight polymers

30

What is the downside of pastes?

Stiff and difficult to apply