EXAM #5: TOPICAL AGENTS Flashcards Preview

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Flashcards in EXAM #5: TOPICAL AGENTS Deck (57):
1

What are the layers of the epidermis?

1) Stratum corneum
2) Stratum granulosum
3) Stratum spinosum
4) Stratum basale

*All of which rest on a basal lamina

2

What is the stratum corneum?

Layer of dead keratinocytes

3

What are the living layers of the epidermis?

1) Stratum granulosum
2) Stratum spinosum (synthesis of epidermal proteins)
3) Stratum basale (cell division)

4

What is the major barrier to percutaneous absorption of drugs?

Stratum corneum i.e. the layer of dead keratinocytes

5

Why is the stratum corneum the major barrier to percutaneous absorption of drugs?

Contains corneyocytes that are:
- Flattened and lipid depleted keratinocytes
- Plasma membrane has been replaced with protein
- Secrete lipids that are hydrophobic

6

What is the rule of thumb for choosing a vehicle for delivering drugs via the skin?

If it is wet, dry it; if it is dry, wet it.

7

What types of vehicles should be used in the scalp and hairy areas?

Lotion
Gels
Solution
Foams
Aerosols

8

What types of vehicles are good for intertriginious areas (two skin areas rubbing together)?

Creams
Lotion
Solutions

9

What vehicles are best for wetting?

Ointment
Creams
Gels
Lotions/solutions

10

What vehicles are good for drying?

Aerosols
Pastes
Powders
Tinctures

11

What is PCA?

Percutaneous Absorption

12

What factors affect PCA?

1) Concentration of drug in the vehicle
2) Drug diffusion coefficient/ molecular size (less MW gets absorbed faster)
3) Lipophilicity
4) Thickness of the stratum corneum
5) Cutaneous vasculature
6) SA of absorptive surface
7) Mucosal surface

13

How will skin inflammation affect PCA?

Inflammation will increase systemic absorption

14

How does skin hydration alter PCA?

Increased hydration increases PCA

15

How will occlusion of a topical medication i.e. in plastic wrap alter PCA?

Increase PCA

16

Explain the basic pathophysiology of acne.

1) Follicular epidermal hyperproliferation causes the formation of a "plug" limits the exit of sebum from the follicle
- Plus = "comedome"
2) Keratin, sebum, and bacteria* accumulate and cause inflammation

*Propionibacterium acnes

17

What topical antibiotics are used to treat acne?

1) Erythromycin
2) Clindamycin
3) Metronidazole
4) Sodium sulfacetamide
5) Azelaic acid
6) Benzoyl Peroxide

18

What is the MOA of Erythromycin and Clindamycin to treat acne?

- Inhibit protein synthesis
- Directed against P. acnes bacteria

19

What is the MOA of Metronidazole to treat acne?

Kills bacteria by disrupting DNA

20

What is the MOA of Sodium Sulfacetamide?

Kills P. acnes by inhibiting dihydropteroate synthetase activity i.e. folic acid

21

What bacteria are treated with Azelaic acid?

P. acnes and S. epidermidis

22

What is the MOA of Azelaic acid?

1) Reduces inflammation (free radical scavenging)
2) Reduces keratinization
3) Keratolytic effects cause desquamation

23

What side effects are associated with Azelaic acid?

1) Lightening of the skin
2) Skin dryness

24

What is the MOA of benzoyl peroxide?

Releases oxygen that is bactericidal against anaerobic bacteria

*Note that benzoyl peroxide does not lead to resistance

25

How is benzoyl peroxide commonly administered?

In combination with erythromycin or clindamycin

26

What is the MOA of Salicylic acid?

Topical keratolytic agent that helps to clear comodomes

27

What are four indications for Retinoid drugs?

1) Acne
2) Psoriasis
3) Skin aging
4) Skin cancer

28

What side effects are associated with the Retinoids?

1) Photosensitivity and increased risk of sunburn
2) Teratogenic

29

What is the MOA of Tretinoin?

Activation of RAA receptors leads to:
1) Reduced cohesiveness of follicular epithelial cells that produce comodomes
2) Codemolytic via increasing mitotic activity of follicular epithelial cells to extrude comedomes
3) Reduces keratinization

30

What drug should NOT be used with Tretinoin?

Benzoyl peroxidase--will inactive the drug

31

What is the MOA of Adapalene?

Via activation of the RAR:
1) Reduced cellular proliferation
2) Reduced inflammation
2) Comedolysis

32

What is the MOA of Isotretinoin?

Suppresses sebum production by inducing apoptosis sebum producing cells in the sebaceous glands

33

What unique adverse effect is associated with Isotretoinoin?

Highly Teratogenic--must be on oral contraceptive to use

34

What is Isotretinoin used to treat?

Oral retinoid used to treat severe acne (this is accutane)

35

What is the MOA of Tazarotene?

This a topical retinoid prodrug. Activation of the RAR is thought to:
- Decreases inflammation
- Reduce epidermal proliferation

36

What are the clinical uses for Tazarotene?

Psoriasis and acne

37

What major adverse effect is associated with Tazarotene?

Teratogenic--must be on oral contraceptives to use

38

What is the clinical indication for Acitretin? What type of drug is this?

Severe, recalcitrant psoriasis

*Oral retinoid

39

What drug-drug interaction should you be aware of with Acitretin?

Alcohol use prolongs half-life for months

*Women are advised to avoid pregnancy for 3x years*

40

What is Calcipotriene used to treat?

Psoriasis

41

What is the MOA of Calcipotriene?

Binds to Vitamin D receptor to induce gene transcription changes that are beneficial in psoriasis

42

What are the side effects associated with Calcipotriene?

- Hypercalcemia
- Hypercalciuria

43

What is the strength of hydrocortisone?

Weak

44

What is the strength of mometasone furoate?

Intermediate

45

What is the strength of clobetasol propionate?

High

46

What potency corticosteroid should be applied to the face and intertriginous areas?

Low i.e. Hydrocortisone

47

What potency corticosteroid should be applied to palms and soles?

High i.e. clobetasol propionate

48

What type of corticosteroid should be avoided in kids?

High i.e. clobetasol propionate

49

What are the side effects of topical corticosteroids?

1) Epidermal atrophy
2) Acne
3) Enhanced fungal infection
4) Delayed wound healing
5) Hypopigmentation

50

What are the side effects of the systemic corticosteroids?

1) HPA-axis suppression
2) Cushing Syndrome
3) Growth retardation

51

What is atopic dermatitis?

Eczema i.e. chronic skin disorder with intense pruritus and dried flaking skin

52

How is eczema treated?

1) Corticosteroids for primary infection
2) Abx for secondary infection e.g. S. aureus

53

What are Psoralens?

- Topical or oral agents that are ACTIVATED BY LIGHT
- On activation they intercalate with DNA to mediate effects

54

List the two Psoralens.

1) Methoxsalen
2) Trioxsalen

55

List the conditions that the Psoralens are used to treat.

1) Alopecia
2) Cutaneous T-cell Lymphoma
3) Eczema
4) Psoriasis

56

What are the short-term toxicities associated with the Psoralens?

1) Nausea
2) Blistering
3) Painful erythema

57

What are the chronic effects of Psoralens?

1) Photoaging
2) Actinic keratoses
3) Nonmelanoma skin cancer

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