Topical Agents Flashcards
What are the 4 layers of the epidermis?
Stratum Corneum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
Which layer of the epidermis has actively dividing cells?
Stratum basale
What is another name for exfoliation?
Desquamatization
What are the absorption pathways of intact skin?
Through appendages (shunt) Transcellular(through corneocytes of S corneum) Hydrophilic drugs Through intercellular lipid domains (most common for small uncharged molecules) Hydrophobic
What are the different vehicles or carriers for topical drugs?
Ointments:water in oil
Creams: oil in water
Gel/Foams: water soluable emulsion
Lotions/solns: powder in water
Aerosols: fine solid or liquid particles in gas
Pastes: Semisolid with finely powdered materials
Tinctures: alcoholic solns
How to select a vehicle based on area of the body?
Scalp/hairy areas Lotion, gels, soln, foam aerosol Intertriginous Areas: Creams, Lotions solutions
How to select a vehicle based on condition of skin:
Ointment (Wetting for Dry and Scaly Skin Cream Gel Lotion/soln Aerosols Pastes Powders Tinctures (Drying for Wet and Oozing skin)
What is the late limiting step for per cutaneous absorption?
Passage through the stratum corneum
What variables determine the rate of percutaneous absorption?
Concentration of drug in vehicle
Partitioning of drug into SC
Intrinsic ability of drug to diffuse across skin layers (MW and Lipophilicity)
Thickness of SC.
What does fick’s Law tell us?
Takes into account all the variables that effect absorption rate
What is the best molecular weight and properties for a topical agent?
What is different about applying topical agents to mucous membranes or inflamed skin?
Will get systemic absorption
What variables can increase PCA?
Inflamed or ulcerated skin
Additional Skin hydration
Occlusion of medication (plastic wrap)
Age of patient (younger will have more systemic effect)
What are the regional differences in absorption?
Mucous membranes(most) Scrotum Eyelids Face Chest and back Arms/Legs Dorda of hands/feet palmar/plantar skin Nails(least)
What are the Tx of Acne?
Abtx, Retinoids, salicylic acid, oral contraceptives, anti-androgens
What are the Topical Antibiotics given for acne?
Erythromycin and clindamycin
Metronidozole
Sodium Sulfacetamide
Azelaic Acid
What is the MOA of Azelaic Acid?
Red. growth of Staph epidermidis Red. inflammation (free rad scavenging) Red. Keratinization Keriolytic effect Drying and lightening of the skin
What is the MOA of Benzoyle Peroxide?
Kills anaerbic bacteria Derived from coaltar keratolytic Comeodolytic(gets rid of plugs) antiinflammatory Use in combo with erythromycin, clindamycin, or adapalene
What is the MOA of Salicylic Acid?
Increases solubilization of stratum corneum. Low conc for acne on face. High conc for warts.
What is an AA of retinoids?
Photosensitivity
What is the MOA of Tretinoin?
Dec cohesiveness of cells that produce comeodones
Increase mitotic activity in follicular cells
Reduces keratinization
What are the drug and envt interactions of Retinoids?
Get degraded in the sun
Benzoyl Peroxide inactivates Retinoic acid
What are the AA and Contraindications of Retinoids?
Pruritis, erythema, dry skin, and increased sun sensitivity
Teratogen(birth defects)
What is a benefit of the Retinoid Adapalene?
More stable. not broken down by benzoyl peroxide
More lipophiclic.
What is the use, AA and MOA of Isotretinoin?
SEVERE acne.
Decreases Sebum production
Significicant teratogen
What is the MOA of Tazarotene?
Topical prodrug that is hydrolyzed into tazarotenic acid
Decreases fine wrinkles by inc. granular cell layers
Decreases inflammation and epidermal hyperproliferation.
What are the AA of Tazarotene?
Teratogen
USE CONTRACEPTIVES!
Photosensitivity
What is used for severe psoriasis that is refractory?
Isoretinoin
What are the AA of Isoretinoin?
Teratogen (wait 3 years before becoming pregnant!)
Half life made even longer if they drink alcohol
What is the MOA of Calciprotriene?
Vitamin D Receptor agonist
Decreases inflammation by inhibiting production of IL2 and IL6
Inhibits lymphocye proliferation
What are the AA of Calcipotriene?
Hypercalcemia and Hypercalciuria
What are the Weak, intermediate, and Super high potency corticosteroids?
Hydrocortisone
Momentasone furoate
Clobetasol propionate
Waht are the AA of Topical corticosteroids?
Topical: Atrophy Acne Enhanced Fungal infection Retards wound healing contact dermatitis Glaucoma, cataracts Systemic: HPA suupression Sushing Synd Growth Retardation
What drugs are in the Psoralen group?
Methoxsalen
Trioxsalen
What are the uses of Photochemical therapy?
Alopecia
Cutaneous T-Cell lymphoma
Eczema
Psoriais
What are the short and long term effects of ST and LT use of phototherapy?
ST: Nausea, blistering, painful erythema
LT: Photoaging, actinic keratosis, non-melanoma skin cancer
