Topical Agents Flashcards by tcarlso 3

What are the layers of the skin from superficial to deep? (5)

Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale

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Where does cell division occur within the skin?

Basal layer

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Which cells of the skin synthesize epidermal proteins?

Spinous layers

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What happens to the cell membrane of skin epithelial cell as they move toward the periphery?

Plasma membrane is replaced by an envelope of insoluble lipid compounds

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What happens in the stratum lucidum?

Cell death

Strengthening of the keratin filaments via crosslinking

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What are the cells that are a part of the stratum corneum?

Corneocytes (flattened and lipid depleted keratinocytes)

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What is the rate limiting step (major barrier) in percutaneous absorption?

Stratum corneum

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What are the appendages (shunt routes) through the skin?

Through hair follicles/ sweat glands

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What are the two routes that drugs can go through corneocytes?

Intracellularly

Transcellularly

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What are the drug “vehicles” for percutaneous drugs?

Inactive part of the preparation that carries the drug

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What are the common vehicles for percutaneous drugs?

Ointments
Creams
Gels/foam

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Where do you not want to apply ointments?

Areas where skin rubs against skin

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What are ointments?

Water in oil emulsion

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What are creams?

Oil in water emulsion

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What are gels/foams?

Water-soluble emulsion

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What types of vehicles are appropriate for intertriginous areas of the body?

Creams
Lotion
Solutions

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What are aerosols?

Fine solid or liquid particles dispersed in gas

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What type of vehicle is appropriate for the scalp and hairy areas?

Lotions
Gels
Solutions
Foams
Aerosols

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Where are lotions, gels, solutions, and aerosols useful?

Scalp and hairy areas

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Where are creams, lotions and solutions used?

Intertriginous areas

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What is the golden rule of dermatology?

If it’s wet, dry it

If it’s dry, wet it

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What are the factors that determine the rate of percutaneous absorption? (4)

Concentration
Partition of drug from the vehicle
Diffusion of drug across the skin layer
Thickness of the stratum corneum

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What is the partition coefficient?

Partitioning of the drug from the vehicle into the stratum corneum

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What is the drug diffusion coefficient?

Molecule aspect of the drug allowing diffusion across the skin layers

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What is Fick's law?

Determines the rate of drug diffusion across a barrier like the skin

How is concentration of a drug related to the rate of percutaneous absorption?

directly related

How is lipophilicity of a drug related to the rate of percutaneous absorption?

Direct

How is molecular size of a drug related to the rate of percutaneous absorption?

Inversely

How is the stratum corneum thickness related to the rate of percutaneous absorption?

Negative relation

How is cutaneous vasculature related to the rate of percutaneous absorption?

Direct

How is area of absorption surface related to the rate of percutaneous absorption?

Direct

Are mucosal surfaces better or worse at absorbing drugs?

Better

How is the moistness related to the rate of percutaneous absorption?

Direct

How is age of patient related to the rate of percutaneous absorption?

Younger = less total body, and increase SA, leading to increased toxicity

How is occlusion of the skin related to the rate of percutaneous absorption?

Increases PCA

What is the effect of the stratum corneum in terms of drug absorption?

Holds drugs, increasing the duration of the drug

What is the most penetrating area for percutaneous absorption? Second most? Least?

Mucus membranes Scrotum Nails

What is the effect of inflamed skin on the rate of absorption of a topical drug? Why?

Increases due to increased permeability and vasodilation in that area

What is the bacteria that is associated with acne?

Propionibacterium acnes

What is the pathophysiology of acne?

Hyperkeratotic infundibulum cause clogging of the pore, in combination with increased sebum production. This causes dilation of hair follicles

What are the drugs that are used to treat acne?

``` Abx Retinoids Salicylic acid Oral contraceptives Anti-androgens ```

What are the main topical abx to treat acne? MOA?

- Erythromycin (macrolide, binds 50s) - Clindamycin (binds 50s) - Metronidazole (intercalating DNA)

What is the MOA of sodium sulfacetamide? Use?

Kills by inhibiting folic acid biosynthesis (sulfa) Abx used to treat acne

What is the MOA of azelaic acid? Use?

Free radicalization Reduces keratinization Abx used to treat acne

What are the side effects of Azelaic acid?

Lightening of skin and drying

What is the MOA of sulfa drugs?

Inhibit folate synthetase

What is the MOA of benzoyl peroxide? Which bacteria does this kill?

Kill anaerobic bacteria be releasing oxygen

True or false: benzoyl peroxide has a high resistant rate

False- no resistance, even with long term use

What are the comedones?

Plugs of the follicle

What does it mean when Benzoyl peroxide if comedolytic?

Breaks comedones

What is the MOA of salicylic acid? What is this used to treat?

Increases solubilization of stratum corneum by breaking keratin hydrogen bonds Low doses = acne High doses = warts

What are retinoids? MOA? Use?

Chemical that have biological activity like Vit A Binds to retinoic acid receptor (RXR or RAR), and induce cell death and differentiation Acne treatment

What are the side effects of the retinoids?

Photosensitivity

What is the MOA of Tretinoin (3)? Use? Adverse effects?

Retinoid for the treatment of acne Decreases cohesiveness of follicular epithelial cells, increases mitotic activity in basal follicular cells, and reduces keratinization, to break the comedone Pruritus and photosensitivity

What is the interaction of retinoid drugs and benzoyl peroxide?

Benzoyl peroxide inactivates retinoid drugs

What is the pregnancy category of Tretinoin?

What is the MOA of Adapalene? Use? Side effects?

Retinoid that reduces cellular proliferation and inflammation Pruritis, xerosis

What is the pregnancy category of Adapalene?

What is the MOA of Isotretinoin? Use? Side effects?

Oral retinoid that suppresses sebum production by inducing apoptosis of cells in sebaceous glands Severe acne Teratogenesis

What is the pregnancy risk of isotretinoin?

Significant teratogenic risk--women must be placed on birth control

What is the MOA of Tazarotene? Use? Side effects?

Retinoid that decreases inflammation and epidermal hyperproliferation Treats psoriasis Photosensitivity and teratogenic

What is the pregnancy risk of tazarotene?

X--contraceptives should be used

What are the four retinoids?

Isotretinoin Tazarotene Tretinoin Adapalene

What are the two types of anti inflammatory drugs for acne?

abx | Retinoids

What are the drugs that inhibit sebaceous gland function?

Antiandrogens Oral contraceptives Isotretinoin

What is psoriasis? What is the most common type?

Autoimmune disease causing inflammation and keratinocyte hyperproliferation Plaque psoriasis

What is the MOA of acitretin? Use? Side effects?

Retinoid with unknown MOA Treats recalcitrant psoriasis Highly teratogenic

What is the effect of EtOH with acitretin? What does this mean?

Converts it to etretinate, that has a half life of 3 months Do not get prego

What is the MOA of calcipotriene? Use? Side effects?

binds to Vit D receptor, and inhibits proliferation of keratinocytes, and inhibits IL-2 and IL-6 by T cells Treats psoriasis Hypercalcemia and hypercalciuria

What are the three major corticosteroids used to treat skin disorders? What is the potency of each?

Hydrocortisone-low Mometasone - med Clobetasol propionate -high

When there is a large surface area to treat, what strength of corticosteroids should be used?

Weak to med

What strength of corticosteroids should be used for facial issues?

Low

What strength of corticosteroids should be used for palms and soles?

High

What is tachyphylaxis that can occur with high potency corticosteroids? How can this be prevented?

Diminished therapeutic benefit with prolonged use Alternate day applications

What are the adverse topical effects to topical corticosteroids?

Atrophy Acne Enhanced fungal infx Retard wound healing

What are the three major adverse systemic effects to topical corticosteroids?

HPA axis suppression Cushing's Growth retardation

What is atopic dermatitis?

Eczema--intense dryness and itching

What causes atopic dermatitis?

Unknown, but predisposed if there are factors that inhibit epidermal barrier

What is the treatment for atopic dermatitis?

Corticosteroids

What is the the photochemical therapy that is used to treat eczema?

Psoralen + UV light (which activates them)

What are the two psoralens that are used?

Methoxsalen | Trioxsalen

What are the uses for Psoralens? (4)

Alopecia Cutaneous T cell lymphoma Eczema Psoriasis

What are the side effects of photochemical therapy?

Nausea, painful erythema | Photoaging

What is the MOA of Mometasone? Use?

*Intermediate* Topical steroid used to treat psoriasis

What is the MOA of Clobetasol? Use?

*Strong* Topical steroid used to treat psoriasis