Dermatologic Pharmacology Flashcards
Percutaneous Pharmacokinetic Variables (4)
Regional: Permeability of skin in that area
Concentration Gradient: drug Mass per unit Time
Dosing Schedule: Longer t 1/2 on skin = less doses/day
Vehicles/Occlusion: stay on skin longer to maximize penetration
Mosturizers
Components with Descriptions (3)
Emollients:
Form oily layer on skin to trap water
Humectants:
Draw water into top layer of skin
Horny Substance (Keratin) Softeners: Loosen bonds to top layer of skin allowing dead skin to fall off and help skin retain water
Sun Protection Component Descriptions
Sunshades (2) Sun Protective Factor
Sunscreen Description and Examples:
PABA (1), Benzophenones (2) Dibenzoylmethanes (2)
Sunshades: Reflect UV rays, Titanium oxide
Sun Protective Factor (SPF): Ratio of erythema with or without sunscreen
Sunscreen: absorbs UV light
PABA - absorb UVB rays
Benzophenones - wide range, less effective than PABA
Dibenzoylmethanes - Active in UVA range, Useful for drug-related photosensitivity
Antiseptics
Soap vs Alcohol (2)
Common Examples with Targets
Glutaraldehyde (2) Amines, Halogens (2) Peroxygens
Soap required for C. difficile
Alcohol faster and effective against bacteria and viruses
Glutaraldehyde: targets cell membrane and Macromolecule cross linking
Quaternary Amines: Targets Cytoplasmic Membrane
Halogens: Targets DNA and acts as oxidizing agent
Peroxygens: Act as oxidizing agents
Chlorhexidine
Mechanism of Action (2) Spectrum of Action (5)
Targets Inner cytoplasmic membrane either decreasing integrity or congealing cytoplasm
Bacterial spores Mycobacteria Yeasts Enveloped Viruses Protozoa
Microbial Resistance Mechanisms Biofilm Actions (4)
Decrease penetration
Neutralize antibiotics with enzymes
Contain persistent non-replicative cells
Slow growth of cells
Wound Management
Disinfecting (2) Priorities (3) Debridement (2)
Skin Growth Agents: Example, MOA, Indication, BBW
Cadexemer iodine and silver used for disinfecting
Prioritize glycemic control, proper nutrition and adequate oxygenation
Debridement appropriate to remove necrotic tissue and debris
Becaplermin:
PDGF to increase cell proliferation and angiogenesis
Used for Chronic Diabetic Foot Ulcers
Malignancy: 3+ tubes increases risk by 4x
Wound Dressings
General Principles (2)
Types Used at Different Stages:
Debridement, Granulation (2) Epithelialization (2)
Keep moist
Don’t expose to air
Hydrogels for Debridement stage
Foam and Low adherence dressings for Granulation
Hydrocolloid and Low adherence dressing for epithelialization
Topical Antibacterial Agents
Examples (3) with Classification and MOA
Bacitracin:
Peptide
Inhibits cell wall synthesis
Neomycin:
Aminoglycoside
Binds 30s subunit to block protein synthesis
Polymixin B
Peptide
Binds phospholipids to alter permeability and damage cytoplasmic membrane
Topical Imidazoles
Mechanism of Action
Examples (4) with Indications (1/1/1/3)
Block ergosterol synthesis
Miconazole: vulvovaginal candidiasis
Clotrimazole: vulvovaginal candidiasis
Efinaconazole: onychomycosis
Ketoconazole: Dermatophytosis, Candidiasis, Seborrheic dermatitis
Ciclopirox
Mechanism of Action and Indications (3)
Disrupts macromolecule synthesis
Dermatophytes
Candidiasis
Malassezia
Terbinafine
Mechanism of Action (3) and Indication
Allylamine
Inhibits squalene epoxidase
Blocks ergosterol synthesis
Dermatophytes
Tolnaftate
Mechanism of Action (2) and Indications (2)
Distorts hyphae, stunts mycelial growth
Dermatophytes
Malassezia
Nystatin*
Mechanism of Action and Indications (2)
Binds sterols to alter membrane permeability
Cutaneous and mucosal Candidiasis
Amphotericin B
Mechanism of Action and Indication
Binds sterols to alter membrane permeability
Cutaneous Candidiasis
Acyclovir
Mechanism of Action and Indication
Guanine analog that inhibits viruses
Orolabial HSV-1 or HSV-2 (herpes labialis)
Pruritis Common Causes (3) Corticoseroid Use Principles (3) TRP Topical Agents (2)
Infections
Neuropathic: compression or degeneration of nerves
Systemic Diseases
Corticosteroids
Useful for pruritis caused by inflammation
Use low potency on face, genitals, skin folds
Use high potency and titrate downwards for other areas
Capsaicin: TRPV1 agonist that desensitizes area
Menthol: TRPM8 agonist
Ectoparasitic Infection Agents
Examples (4) with Mechanisms of Action
Malathion: organophosphate cholinesterase inhibitor
Permethrin: bind Na+ channels to block repolarization
Ivermectin: Bind Glu-Chloride channel to hyperpolarize
Oral
Lindane: Disrupt GABA transmission
Used as last resort (due to toxicity)
Acne Vulgaris Treatment
Topical Retinoids: Examples (3) Adverse Effects (3/2/1)
Oral Retinoid: Example, Adverse Effects (2)
Tretinoin: Local irritation, sun sensitivity, fish allergies
Adapalene: Local irritation, sun sensitivity
Tazarotene: Pregnancy Category X
Isoretinoin: Teratogenic, Hypertriglyceridemia
Acne Vulgaris Treatment
Topical Antimicrobials: Examples (3) Adverse Effects (2/1/0)
Oral Agents: Examples (4) Adverse Effects (2/2/1/2)
Benzoyl Peroxide: local irritation, may bleach things
Clindamycin: Pseudomembranous colitis
Erythromycin
Tetracycline/Doxycycline: Contraindicated in pregnancy, photosensitivity
Minocycline: contraindicated in pregnancy, drug SLE
Erythromycin/Azithromycin: GI distress
TMP-SMX: Stevens Johnson syndrome, epidermal necrolysis
Azaleic Acid
Classification, Effects (2) Uses (2)
Dicarboxylic acid
Kills acne bacteria
Decreases keratin production
Acne
Post-inflammatory hyperpigmentation
Acne Vulgaris Treatment
Hormonal Agents: Examples (2) Adverse Effects
Oral Contraceptives: Thromboembolic events
Sprionolactone: Contraindicated in pregnancy
Used for women with menstrual-related breakouts
Psoriasis Therapy First Line (2) Other Topical Agents (6) UV Options with Descriptions (2)
Emollients and Corticosteroids
Vitamin D (reduce keratin) Tar Tazarotene (retinoid) Calcineurin Inhibitors Anthralin Salt Water bath
UVB: done to point of erythema, immunomodulator
Photochemotherapy (PUVA): used with ingested photosensitizer psoralen, increased melanoma risk
Apremilast
Mechanism of Action (3) Indication, Delivery, Adverse Effects (2)
Inhibits PDE4 causing increased cAMP
Decreases NO synthase, TNFa, IL-23
Increases IL-10
Psoriasis
Oral
Severe diarrhea
Headache
Ustekinumab
Mechanism of Action (2) Indications (3) Delivery, Adverse Effect
monoclonal Ab against IL-12 and IL-23
Psoriasis
Psoriatic Arthritis
Crohn Disease
Subcutaneous injection
Increased risk of infection
Secukinumab
Mechanism of Action (2) Indications (3) Delivery, Adverse Effect
monoclonal Ab against IL-17A
Psoriasis
Psoriatic Arthritis
Ankylosing Spondylitis
Subcutaneous injection
Increased risk of infection
Actinic Keratosis
Topical Treatments: MOA, Adverse Effects
5-Fluorouracil, Imiquimod, Ingenol Mebutate, Diclofenac
5-Fluorouracil:
Inhibits thymidylate synthase, blocks DNA synthesis
Inflammation and destructive lesions
Imiquimod:
stimulates local cytokines
Ingenol Mebutate:
Initially disrupts plasma membranes/mitochondria causing cell necrosis
Then neutrophil-mediated Ab-dependent cell toxicity
Diclofenac:
NSAID
Skin Cancer Therapy Examples with MOA
Basal Cell Carcinoma (2) Melanoma (2)
Basal Cell:
Vismodegib or Sonidegib
Oral SHH pathway inhibitors
Melanoma
Chemo: Dacarbazine
Vemurafenib: MAPK inhibitor, causes apoptosis
Alopecia Treatments
Examples (3) with MOA
Minoxidil:
Causes K+ channel opening that leads to vasodilation
Finasteride:
Oral DHT inhibitor (can cause sex dysfunction)
Diphenylcyclopropenone (DPCP):
Topical immunotherapy, increases hair growth by causing contact dermatitis
Used in Alopecia Areata
