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Unit 3 D&D > DD 03-05-14 08-09am Dermatologic Therapeutics - Armstrong > Flashcards

DD 03-05-14 08-09am Dermatologic Therapeutics - Armstrong Flashcards

1
Q

Stratum corneum & Topical meds

A

Stratum corneum
= primary barrier to percutaneous absorption of topical meds
= a “brick & mortar” structure, where keratinocytes represent bricks & intercellular lipids act as mortar

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2
Q

Drug formulations for topical medications

A

consist of active ingredient in vehicle base

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3
Q

Categories of Factors that influence effective percutaneous absorption of topical medications

A

(a) drug factors

(b) patient factors

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4
Q

Drug factors affecting percutaneous absorption include

A
  • Active drug concentration
  • Composition of the vehicle
  • Molecular size of the drug or prodrug
  • Lipophilicity of the drug
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5
Q

Patient factors affecting percutaneous absorption of topical medications include:

A
  • Presence of barrier disruption
  • Anatomic location (including thickness of the stratum corneum)
  • Skin hydration
  • Occlusion
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6
Q

Affect of vehicle & active ingredient concentration on Percutaneous absorption:

A
  • Given same vehicle, cutaneous absorption is directly proportional to concentration of active ingredient in the medication
  • Given the same concentration of active ingredient, cutaneous absorption can differ when ingredient is embedded in different vehicles
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7
Q

Molecular size of the drug & absorption

A
  • Molecular size of drug affects its absorption at the site of action
  • When absorbed through passive diffusion, molecules need to traverse a tortuous path through the intercellular lipid domains (“mortar”)
  • Typically, diffusion of a compound is inversely proportional to its molecular size
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8
Q

Affect of lipids in the stratum corneum on Percutaneous absorption

A
  • Stratum corneum contains a mixture of lipidsthat includes ceramides, cholesterol and fatty acids
  • Lipophilic topical agents are more likely to permeate the skin than hydrophilic agents
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9
Q

Skin hydration & Percutaneous absorption

A
  • Affects percutaneous absorption in important ways, sometimes by several folds.
  • Occlusion of skin often leads to markedly increased skin hydration.
  • Thus, active ingredients delivered in the form of an ointment, tape, or to the skin folds, reach much higher concentrations b/c occlusion prevents loss of med by evaporation, friction, or exfoliation.
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10
Q

Anatomic location & Percutaneous absorption

A

Generally, absorption is LOWER in anatomic regions where stratum corneum is thicker
= palms & soles

In contrast, percutaneous absorption is HIGHER in areas where the stratum corneum is thinner
= eyelids & scrotum

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11
Q

Classification of Vehicles

A
  • Ointments
  • Creams
  • Gels
  • Lotions/Solutions
  • Foams
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12
Q

Ointment defn.

A

Water in Oil emulsion

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13
Q

Creams defn.

A

Oil in Water emulsion

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14
Q

Gels defn.

A

Semisolid emulsion in alcohol base

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15
Q

Lotions/Solutions defn.

A

Powder in water (some oil in water)

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16
Q

Foams defn.

A

Pressurized collections of gaseous bubbles in a matrix of liquid film

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17
Q

Ointments - Characteristics (Pros & Cons)

A

PROS:

  • Strong potency of active ingredients delivered thus
  • hydrating
  • very low sensitization risk or irritation risk

CONS:

  • some pts dislike their greasiness
  • ointments may stain clothing (educate pts)
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18
Q

Body sites for ointment use

A

Most amenable = non-intertreginous sites
= places where skin isn’t touching skin
= i.e., NOT the axilla, anogenital region, nares, skin folds of the breasts, between digits, etc.

Best to avoid on;

  • face
  • hands
  • groin
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19
Q

Creams - Characteristics

A
  • Moderate potency of active ingredients delivered thus
  • Some hydration, but less than ointments
  • Significant sensitization risk
  • Low irritation risk
  • High rate of acceptance by patients
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20
Q

Body sites for cream use

A

Amenable in virtually all body sites

Avoid in sites w/ maceration

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21
Q

Gels - Characteristics

A
  • Strong potency of active ingredients delivered thus - Drying
  • Significant sensitization risk
  • Relatively high irritation risk
  • Pt preference for gels is variable
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22
Q

Body sites for gel use

A

Most amenable:

  • oral mucosal surfaces
  • scalp

Avoid on:

  • fissures
  • erosions
  • macerated regions
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23
Q

Lotions/Solutions - Characteristics

A
  • Low potency of active ingredients delivered thus
  • Variably drying
  • Significant sensitization risk
  • Moderate irritation risk
  • Relatively high rate of pt acceptance
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24
Q

Body sites for Lotion/Solution use

A

Most amenable:

  • scalp
  • intertriginous areas (areas where skin touches skin)

Avoid on:

  • fissures
  • erosions
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25
Q

Foams - How it works as a vehicle

A
  • Foam matrix is stable at room temp but readily melts at body temp
  • After applied to skin, volatile components (alcohol, water) quickly evaporate
  • –> leave behind lipid & polar components containing supersaturated active ingredients to interact w/ lipids of the stratum corneum
  • –> These supersaturated solutions enable maximal delivery of active ingredients into skin

Alcohol (component of foam matrix)

  • may play role in altering stratum corneum’s barrier properties
  • –> improved penetration of active ingredient
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26
Q

Foams - Characteristics

A
  • Relatively new vehicle for topical agents
  • Strong potency of active ingredients delivered this
  • Quick-drying
  • Stain-free
  • Leave almost no residue
  • High pt preference for foam
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27
Q

Body sites for Foam use

A

Most amenable:
- hair-bearing areas

Avoid on:

  • fissures
  • erosions
28
Q

3 Considerations for Selecting an Appropriate Vehicle

A
  • Anatomic location
  • Contact allergy/sensitization
  • Irritancy
29
Q

Vehicles for hair-bearing sites

A

Use solution or foam vehicle over ointment

30
Q

Contact Allergy/Sensitivity in Vehicles

A

Various water-based vehicles (creams, lotions, solutions) contain preservatives that may increase risk of contact allergy and sensitization

Preservatives include known allergens likeL

  • parabens
  • formalin releasers
31
Q

Irritancy in Vehicles

A

= Most notably associated w/ high concentrations of propylene glycol, other types of alcohols, & certain acidic vehicle ingredients
- EX: Avoid using formulations containing alcohol or salicylates on extensively fissured, eroded, or macerated areas –> stinging & burning

32
Q

Fingertip Unit (FTU) defn.

A

= the amount of ointment dispensed from a 5 mm diameter nozzle that is applied to the distal third of the index finger, from the crease under the distal interphalangeal joint to the fingertip

33
Q

1 FTU = how many grams?

A

1 FTU = 0.5 g

34
Q

FTUs required for one application to the face & neck

A

2.5 FTU (1.25 g)

35
Q

FTUs required for one application to the Trunk (front or back)

A

7 FTU (3.5 g)

36
Q

FTUs required for one application to 1 arm

A

3 FTU (1.5 g)

37
Q

FTUs required for one application to 1 hand, both sides

A

1 FTU (0.5 g)

38
Q

FTUs required for one application to 1 leg

A

6 FTU (3 g)

39
Q

FTUs required for one application to 1 foot

A

2 FTU (1 g)

40
Q

1 gram of cream covers approximately…

A

10 cm x 10cm area of skin

41
Q

Spread of 1 gram of ointment vs. 1 gram of cream

A

1 g ointment spreads 10% further than 1 g of cream

42
Q

Grams necessary to treat entire body of an adult man

A

~ 20 g

= ~280 g/week if applied twice daily for 1 week

43
Q

Quantities of ointment to dispense in children

A

= differ according to age due to different body surface areas

44
Q

Ointment amount for 3-6 mo old

A

1 FTU for:

  • face & neck
  • arm & hand
  • trunk (front)
  1. 5 FTU for:
    - leg & foot
    - trunk (back) including buttocks
45
Q

Ointment amount for 1-2 yo

A
  1. 5 FTU for:
    - face & neck
    - arm & hand
  2. 5 FTU for:
    - leg & foot
    - trunk (front)

3 FTU for: trunk (back) including buttocks

46
Q

Ointment amount for 3-5 yo

A

1.5 FTU for: face & neck

2 FTU for: arm & hand

3 FTU for:

  • leg & foot
  • trunk (front)

3.5 FTU for: trunk (back) including buttocks

47
Q

Ointment amount for 6-10 yo

A

2 FTU for: face & neck

  1. 5 FTU for: arm & hand
  2. 5 FTU for: trunk (front)
  3. 5 FTU for: leg & foot

5 FTU for: trunk (back) including buttocks

48
Q

Molecular Mechanism of Action of Glucocorticosteroids

A

Glucocorticosteroids bind to to their receptors, usually in cytoplasm of most cells

  • –> release of 90 kDa heat shock protein
  • –> subseuqent nuclear localization signals facilitate translocation of glucocorticoid receptor complex into nucleus

In nucleus, glucocorticoid receptor forms dimer

  • –> binds glucocorticoid response element of promoter region of steroid-responsive genes
  • Associated with downstream molecular events
49
Q

Downstream molecular events associated with binding of glucocorticoid receptor to glucocorticoid response element

A
  • Alteration of transcription rate, mRNA production, & pro-inflammatory protein synthesis
  • Interaction w/TFs & their cofactors that have roles inflammatory response (including cAMP response element binding protein (CREB)-binding protein)
  • Inhibition of NF-κB pathway
  • Interaction w/ activating protein 1 (AP-1)
  • Inhibition of TNF-α, granulocyte–macrophage colony-stimulating factor, and several interleukins (e.g. IL-1, IL-2, IL-6, IL-8)
  • Inhibition of cyclooxygenase & adhesion molecules such as intercellular adhesion molecule-1 and E-selectin
50
Q

Inhibition of NF-κB pathway by glucocorticoids

A 
---> reduction in transcription of genes of chronic inflammation 
Including genes for:
- cytokines
- adhesion molecules
- inflammatory enzymes
- growth factors
51
Q

Activating Protein 1 (AP-1)

A

= a collective term for the heterodimeric transcription factor composed of c-jun, c-fos & activating transcription factor
= controls transcription of growth factor & cytokine genes

52
Q

General Classification of Topical Steroids

A
  • Lots of topical glucocorticosteroid meds w/ wide range of potency
  • Generally, seven classes based on potency
    = 1. Superpotent to 7. Very low-potency
  • developed based on vasoconstrictor assays
  • greatly influenced by vehicle
53
Q

Hydrocortisone 2.5% (cream or ointment) - class

A 
“The Gentle Touch” 
- belongs to class 7 (lowest potency class)
54
Q

Hydrocortisone 2.5% cream or ointment is efficacious for…

A
  • mild eczema in children & adults
  • inflammatory dermatoses involving anatomic regions such as face, intertriginous areas, or groin (where mid to high-potency topical steroids may be contraindicated)
55
Q

Triamcinolone Acetonide 0.1% (cream or ointment) - class & general info

A

“The Almost All-Purpose Weapon”

  • affordable & readily available in many different tube sizes (even in 1lb jar!)
  • belongs to class 4 (mid-potency class)
56
Q

Triamcinolone Acetonide 0.1% cream or ointment is efficacious for…

A

Most moderate spongiotic dermatoses involving trunk & extremities, including:

  • eczematous dermatitis
  • atopic dermatitis
  • allergic contact dermatitis
  • arthropod bites
  • id reactions
  • drug reactions

Long-term use NOT recommended for facial, intertriginous, & groin lesions

57
Q

Clobetasol Propionate 0.05% (cream or ointment) - class

A

“Hercules”

  • belongs to Class 1 of topical steroids
  • considered one of the most potent topical steroids
58
Q

Clobetasol propionate 0.05% cream or ointment is best used for & best avoided in…

A

Eruptions that necessitate relatively rapid amelioration, such as:

  • contact dermatitis
  • acute drug eruptions

Should be avoided on face, intertriginous areas, or groin, where the skin is relatively thin.

Longer-term use of clobetasol requires monitoring of development of adverse effects.

59
Q

General Considerations for Selecting a Topical Steroid

A

Take into account:

  • severity of condition
  • location of lesion
  • need for hydration or drying effect

Should be aware of potential for sensitization or irritation of certain types of vehicles.

Potency based on vehicle.

60
Q

Potency of same active ingredient in ointment vs. other forms (except foam)

A
  • Due to occlusive nature of an ointment vehicle, same active glucocorticosteroid ingredient in ointment form will often be more potent than same ingredient in cream, lotion, or solution
    improved penetration of medication
61
Q

Body sites to avoid in potent/superpotent topical steroids

A
  • face
  • skin folds (axillary & intertriginous folds)
  • groin areas

<—due to risk of epidermal atrophy & potential for steroid-induced rosacea/perioral dermatitis on face

62
Q

Adverse Effects of Topical Glucocorticosteroids - general concept & types

A

Generally, more potent topical steroids are associated w/ greater adverse effects.

Most common adverse effect = skin atrophy

Extensive and long-term use of potent or super-potent topical steroids have been associated w/ systemic side effects
<— increased systemic absorption of percutaneously delivered active ingredient

63
Q

Adverse Effects of Topical Glucocorticosteroids - Skin atrophy

A
  • Most common adverse effect of topical glucocorticosteroids
  • Most commonly associated w/ long-term use of potent to super-potent topical steroids

May manifest as…

  • shiny, thin skin
  • telangiectasia
  • striae formation

Areas w/ baseline relatively thin epidermis (face, intertriginous areas) are more susceptible to developing skin atrophy compared to other areas of the body.

64
Q

Adverse Effects of Topical Glucocorticosteroids - Systemic side effects

A
  • seen w/ extensive & long-term use of potent or super-potent topical steroids
  • due to increased systemic absorption of percutaneously delivered active ingredient

Potential systemic side effects include:

  • adrenal suppression
  • Cushing’s syndrome
  • growth retardation in children

Currently, AAD guideline for max use of class I topical steroids is to not exceed 50 g / week.

65
Q

Psoriasis & Atopic dermatitis patients, with long term use of glucocorticosteroids

A

Such pts may require longer-term use of potent topical steroids to cover larger body surface areas than other dermatologic patient populations.
—> Systemic adverse effects of topical steroids are particularly relevant to these populations

Unit 3 D&D (18 decks)

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